Projection system and method for controlling projection system

ABSTRACT

A projection system includes a first projector that projects an image based on image data in a first projection direction, a second projector that projects an image based on image data in a second projection direction, and a storage section that stores the image data representing the image projected by the first projector. The projection system can switch the image projected by the second projector to the image based on the image data stored in the storage section.

CROSS-REFERENCE

The entire disclosure of Japanese Patent Application No. 2016-232195,filed Nov. 30, 2016 is expressly incorporated by reference herein.

BACKGROUND 1. Technical Field

The present invention relates to a projection system and a method forcontrolling the projection system.

2. Related Art

In a projector of related art, to allow a large amount of information tobe displayed, there is a known projector that projects a plurality ofimages on a single projection surface (see JP-A-2000-10189, forexample). The projector described in JP-A-2000-10189 displays two imageson a single screen, an image supplied from a personal computer or anyother external information apparatus and an image captured with adocument camera.

There is a demand for increase in the amount of information projected bya projector. For example, it is conceivable that when a projected imageis changed, the image before the change is also projected for comparisonpurposes. To achieve the requirement by using a projector of relatedart, for example, the images need to be reduced in size beforeprojected.

SUMMARY

An advantage of some aspects of the invention is to allow a projector toincrease the amount of information to be projected.

An aspect of the invention is directed to a projection system includinga first projector that projects an image based on image data in a firstprojection direction, a second projector that projects an image based onimage data in a second projection direction, and a storage section thatstores the image data representing the image projected by the firstprojector, and the image projected by the second projector is allowed tobe switched to the image based on the image data stored in the storagesection.

According to the aspect of the invention, an image projected by aprojector can be projected by another projector. Therefore, the imageprojected by the projector can be changed to another image, and theimage before the change can be projected by the other projector, wherebythe number of images projected by the projectors can be substantiallyincreased. The projectors can therefore project a larger amount ofinformation.

The projection system according to the aspect of the invention mayfurther include an acceptance section that accepts an instruction input,and the image projected by the second projector may be switched to theimage based on the image data stored in the storage section inaccordance with the instruction input accepted by the acceptancesection.

According to the aspect of the invention with this configuration,switching the image projected by the second projector to the image basedon the image data stored in the storage section in accordance with theinstruction input allows the second projector to project the imageprojected by the first projector. The second projector therefore doesnot need to be set in advance at the state in which no image isprojected, whereby convenience provided by the projection system can beimproved.

Another aspect of the invention is directed to a projection systemincluding a first projector including a first acquisition section thatacquires image data, first projection section that projects an imagebased on the image data acquired by the first acquisition section, afirst storage section that stores the image data representing the imageprojected by the first projection section, and a first communicationsection that transmits the image data stored in the first storagesection to the second projector, and a second projector including asecond acquisition section that acquires image data, a second projectionsection that projects an image based on the image data acquired by thesecond acquisition section, a second communication section that receivesthe image data from the first projector, and a second storage sectionthat stores the image data received by the second communication section,and the second projector can perform an action in which the secondprojection section projects the image based on the image data acquiredby the second acquisition section and an action in which the secondprojection section projects the image based on the image data stored inthe second storage section with the two actions switched from one to theother.

According to the aspect of the invention, the image projected by thefirst projector can be projected by the second projector. Therefore, ina case where the image projected by the first projector is changed toanother image, the image before the change can be projected by thesecond projector, whereby the number of images projected by the firstprojector can be substantially increased. The projectors can thereforeproject a larger amount of information.

In the projection system according to the aspect of the invention, thefirst projector may include a switching control section that producescontrol data that instructs the second projector to perform imageswitching and causes the first communication section to transmit thecontrol data to the second projector, and the second projector, uponreception of the control data via the second communication section, mayswitch the action in which the second projection section projects theimage based on the image data acquired by the second acquiring sectionto the action in which the second projection section projects the imagebased on the image data stored in the second storage section and viceversa.

According to the aspect of the invention with this configuration,transmission of the control data from the first projector allows theimage projected by the second projector to be switched to the imageprojected by the first projector. The operation required to perform theprojection image switching in the projection system can therefore besimplified, whereby the convenience provided by the projection systemcan be improved.

In the projection system according to the aspect of the invention, thefirst projector projects an image for operation based on datarepresenting the image for operation and include an acceptance sectionthat accepts operation performed on the image for operation projected bythe first projection section, and the switching control section mayproduce the control data based on the operation accepted by theacceptance section and cause the first communication section to transmitthe control data to the second projector.

According to the aspect of the invention with this configuration,operation using the image for operation can readily instruct projectionimage switching in the projection system.

In the projection system according to the aspect of the invention, thefirst projector may include a position detecting section that detects aposition input and an image producing section that produces an imagebased on a position detected by the position detecting section. Thefirst projection section may project an image based on combined imagedata formed of image data representing the image produced by the imageproducing section combined with the image data acquired by the firstacquisition section. The first storage section may store the combinedimage data. The first communication section may transmit the combinedimage data stored in the storage section to the second projector.

According to the aspect of the invention with this configuration, in acase where a projector produces an image based on a position input andprojects the image, the other projector can project a projection imagecontaining the produced image.

In the projection system according to the aspect of the invention, thefirst projector may include a third projection section that projects animage in a direction different from a direction in which the firstprojection section projects an image, and the first projector can causethe third projection section to project an image based on the image dataacquired by the first acquisition section and an image based on theimage data stored in the first storage section with the two imagesswitched from one to the other.

According to the aspect of the invention with this configuration, aprojection image projected by a projector can be projected by the otherprojector, and the same projector can project the projection image in adifferent direction. Projection images projected in a plurality ofdirections can therefore be switched from one to another with highflexibility, whereby the convenience provided by the projection systemcan be further improved.

In the projection system according to the aspect of the invention, in acase where the third projection section displays the image based on theimage data stored in the first storage section, the orientation of theimage can be changed.

According to the aspect of the invention with this configuration, animage projected by a projector can be projected in an orientation thatallows a person who views the image to readily visually recognize theimage.

In the projection system according to the aspect of the invention, thesecond projector may include a fourth projection section that projectsan image in a direction different from a direction in which the secondprojection section projects an image, and the second projector can causethe fourth projection section to project an image based on the imagedata acquired by the second acquisition section and an image based onthe image data stored in the second storage section with the two imagesswitched from one to the other.

According to the aspect of the invention with this configuration, aprojection image projected by a projector can be projected by the otherprojector, and the same projector can project the projection image in adifferent direction. Projection images projected in a plurality ofdirections can therefore be switched from one to another with highflexibility, whereby the convenience provided by the projection systemcan be further improved.

In the projection system according to the aspect of the invention, in acase where the fourth projection section projects the image based on theimage data stored in the second storage section, the orientation of theimage can be changed.

According to the aspect of the invention with this configuration, animage projected by a projector can be projected in an orientation thatallows a person who views the image to readily visually recognize theimage.

Another aspect of the invention is directed to a method for controllinga projection system including a first projector that projects an imagebased on image data in a first projection direction and a secondprojector that projects an image based on image data in a secondprojection direction, the method including storing the image datarepresenting the image projected by the first projector and switchingthe image projected by the second projector to the image based on thestored image data.

According to the aspect of the invention, an image projected by aprojector can be projected by another projector. Therefore, the imageprojected by the projector can be changed to another image, and theimage before the change can be projected by the other projector, wherebythe number of images projected by the projectors can be substantiallyincreased. The projectors can therefore project a larger amount ofinformation.

Another aspect of the invention is directed to a method for controllinga projection system including a first projector that projects an imagebased on image data in a first projection direction and a secondprojector that projects an image based on image data in a secondprojection direction. The first projector causes a first acquisitionsection to acquire image data, projects an image based on the image dataacquired by the first acquisition section, stores the image data on theprojected image, and transmits the stored image data to the secondprojector, and the second projector causes a second acquisition sectionto acquire image data, projects an image based on the image dataacquired by the second acquisition section, and receives the image datafrom the first projector, stores the received image data, and performsan action of projecting the image based on the image data acquired bythe second acquisition section and an action of projecting the imagebased on the stored image data with the two actions switched from one tothe other.

According to the aspect of the invention, the image projected by thefirst projector can be projected by the second projector. Therefore, ina case where the image projected by the first projector is changed toanother image, the image before the change can be projected by thesecond projector, whereby the number of images projected by the firstprojector can be substantially increased. The projectors can thereforeproject a larger amount of information.

The aspect of the invention can be implemented in a variety of formsother than the projection system and the method for controlling theprojection system described above. For example, to carry out thecontrolling method described above, the aspect of the invention can beimplemented in the form of a program executed by a computer (orprocessor). The aspect of the invention can also be embodied, forexample, in the form of a recording medium on which the programdescribed above is recorded, a server apparatus that distributes theprogram, a transport medium that transports the program described above,or a data signal carrying the program described above embodied in acarrier wave.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a schematic configuration diagram of a projection systemaccording to an embodiment.

FIG. 2 is another schematic configuration diagram of the projectionsystem.

FIG. 3 is a functional block diagram of the projection system.

FIG. 4 is a block diagram of a projector.

FIG. 5 is a block diagram of a projector.

FIG. 6 is a block diagram of a projector.

FIG. 7 shows an aspect of GUI operation.

FIG. 8 is a flowchart showing actions of a projector.

FIG. 9 is a flowchart showing actions of the projector.

FIG. 10 is a flowchart showing actions of a projector.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIGS. 1 and 2 are schematic configuration diagrams of a projectionsystem 1 according to an embodiment to which the invention is applied.

The projection system 1 is a system including a plurality of projectorsand includes three projectors 11, 13, and 15 in the present embodiment.The plurality of projectors 11, 13, and 15 are installed in the sameroom as shown, for example, in FIG. 1. The room where the projectionsystem 1 is installed has walls, a ceiling, and a floor, and the wallsand the ceiling are each formed of a flat surface and can be used asprojection surfaces on which the projectors 11, 13, and 15 projectprojection images. In the following description, wall surfaces arecalled flat surfaces PL1, PL2, and PL3, a ceiling surface is called aflat surface PL4, and a floor surface is called a flat surface PL5. Theprojectors 11, 13, and 15 can each project image light on a projectionsurface, such as a wall surface, a curtain, and a plate, to form aprojection image on the projection surface. In the present embodiment,the image light is projected on the flat surfaces PL1 to PL4 (projectionsurfaces). Each of the projection surfaces on which an image isprojected is not limited to a flat surface and may instead be a curvedsurface. For example, it is conceivable that the projectors 11, 13, and15 use a blackboard as each of the flat surfaces PL1, PL2, and PL3, andthe ceiling surface on the other hand can be slightly curved so as to bereadily viewed from a variety of positions in the room. In this case,the surface PL4 is a curved surface. The projectors 11 and 13 correspondto a first projector. The projectors 11, 13, and 15 correspond to asecond projector.

The projectors 11, 13, and 15 can be arbitrarily changed in terms ofdetails and installation states thereof. In the present embodiment, theprojector 11 is fixed to the flat surface PL1, the projector 13 is fixedto the flat surface PL2, and the projector 15 is fixed to the flatsurface PL3. That is, the projectors 11, 13, and 15 are each installedon a wall surface. The installation state is what is called wall-hanginginstallation. In this case, the projectors 11, 13, and 15 are close tothe flat surfaces PL1, PL2, PL3, and PL4, which are projection surfaces.The projectors 11, 13, and 15 are each therefore preferably ashort-focal-length projector, which is capable of proximity projection.

The projectors 11 and 13 can each project image light in two directionsto project projection images. The projector 15 projects image light inone direction.

In the installation state shown in FIGS. 1 and 2, the projector 11projects a projection image P1 on the flat surface PL1 and projects aprojection image P2 on the flat surface PL4. The projector 13 projects aprojection image P3 on the flat surface PL2 and projects a projectionimage P4 on the flat surface PL4. The projector 15 projects a projectionimage P5 on the flat surface PL3.

The projectors 11 and 13 can change the orientation of the projectionimages by using image processing that will be described later. Forexample, the projector 11 can switch the state of the projection imageP2 projected on the flat surface PL4 between the state shown in FIG. 1and the state shown in FIG. 2. The projection image P2 in FIG. 1 and theprojection image P2 in FIG. 2 are turned upside down with respect toeach other. In another expression, the projection image P2 in FIG. 1 isprojected in the orientation in which the projection image P2 in FIG. 2is rotated in the plane thereof by 180 degrees. Similarly, theprojection image P4, which is projected by the projector 13 on the flatsurface PL4, is projected in the orientation shown in FIG. 1 or theorientation shown in FIG. 2, which is the orientation in FIG. 1 rotatedby 180 degrees. The state shown in FIG. 1 and the state shown in FIG. 2can be switched from one to the other. The projectors 11 and 13 turn theprojection images P2 and P4, which are projected on the flat surface PL4(ceiling surface), upside down in accordance with the position of aperson who views the projection images P2 and P4 to allow the viewer toreadily view the projection images P2 and P4. For example, in a casewhere a person who views the projection image P2 is present immediatelybelow the projector 11, the projector 11 may project the projectionimage P2 in such a way that the upper side of the image faces the sideclose to the flat surface PL1, as shown in FIG. 2.

In a case where any of the projectors 11, 13, and 15 projects an imageon the flat surface PL4, which is the ceiling, or a rear-side wallsurface (not shown) of the room where the projectors 11, 13, and 15 areinstalled, the projectors 11, 13, and 15 may project a horizontallyreversed mirror image. For example, in a scene in which the installationroom is a classroom or a lecture room, and a mirror is attached to adesktop used by pupils, students or lecture participants, the pupils,the students or the lecture participants can visually recognize aprojection image projected on the flat surface PL4 or on the rear-sidewall and displayed on the mirror in the proper orientation of the imagewithout looking up at the ceiling or looking back but in aforward-facing posture.

FIG. 3 is a functional block diagram of the projection system 1. FIG. 3shows primary functional blocks that form the projectors 11, 13, and 15,and the configuration of each of the projectors will be described laterin detail.

The projection system 1 includes a wireless communication apparatus 9,as shown in FIG. 3. The wireless communication apparatus 9 performsone-to-one wireless data communication with each of the projectors 11,13, and 15 or achieves one-to-multiple wireless data communication amongapparatus formed of the projectors 11, 13, and 15 and the wirelesscommunication apparatus 9. The thus functioning wireless communicationapparatus 9 forms a communication network 10, which allows two-waywireless data communication to be performed among the projectors 11, 13,and 15. Specifically, the wireless communication apparatus 9 can be anaccess point or a router in a wireless LAN (including Wi-Fi (registeredtrademark)). The wireless communication apparatus 9 may instead beconfigured to perform Bluetooth (registered trademark) or any othershort-range wireless communication with the projectors 11, 13, and 15.

The projector 11 includes a control section 21, which controls eachportion of the projector 11, a storage section 22, which stores avariety of data, a wireless communication section 23, which performswireless data communication with the wireless communication apparatus 9,and an image processing section 24, which processes an image to beprojected. The projector 11 further includes a projection section 25,which projects the projection image P1 on the flat surface PL1 (FIG. 1),and a projection section 26, which projects the projection image P2 onthe flat surface PL4 (FIG. 1). The wireless communication section 23performs wireless data communication, such as a wireless LAN (includingWi-Fi) and Bluetooth (registered trademark), over the communicationnetwork 10.

The projector 13 includes a control section 31, which controls eachportion of the projector 13, a storage section 32, which stores avariety of data, a wireless communication section 33, which performswireless data communication with the wireless communication apparatus 9,and an image processing section 34, which processes an image to beprojected. The projector 13 further includes a projection section 35,which projects the projection image P3 on the flat surface PL2 (FIG. 1),and a projection section 36, which projects the projection image P4 onthe flat surface PL4 (FIG. 1). The wireless communication section 33performs wireless data communication, such as a wireless LAN (includingWi-Fi) and Bluetooth (registered trademark), over the communicationnetwork 10.

The projector 15 includes a control section 51, which controls eachportion of the projector 15, a storage section 52, which stores avariety of data, a wireless communication section 53, which performswireless data communication with the wireless communication apparatus 9,and an image processing section 54, which processes an image to beprojected. The projector 15 further includes a projection section 55,which projects the projection image P5 on the flat surface PL3 (FIG. 1).The wireless communication section 53 performs wireless datacommunication, such as a wireless LAN (including Wi-Fi) and Bluetooth(registered trademark), over the communication network 10.

An image source apparatus (not shown) that supplies image data can beconnected to each of the projectors 11, 13, and 15. The image sourceapparatus can, for example, be a notebook PC (personal computer), adesktop PC, a tablet terminal, a smartphone, or a PDA (personal digitalassistant). The image source apparatus may instead be a videoreproducing apparatus, a DVD (digital versatile disk) player, a Blu-raydisk player, a hard disk recorder, a television tuner, a set top box ofa CATV (cable television), or a video game console.

The projector 11 acquires image data from an image source and projectsimages based on the acquired image data via the projection sections 25and 26 under the control of the control section 21. The image data usedby the projector 11 can be selected from image data input from the imagesource apparatus and image data stored in the storage section 22. Animage source of the projection image P1 projected by the projectionsection 25 and an image source of the projection image P2 projected bythe projection section 26 can be separately selected. The image sourceof the projection image P1 and the image source of the projection imageP2 may be different image sources or the same image source. Theprojector 11 has the function of swapping the image source of theprojection image P1 projected by the projection section 25 and the imagesource of the projection image P2 projected by the projection section 26based, for example, on a user's operation. The projector 11 can thusinterchange the projection images P1 and P2 being projected.

The projector 13 acquires image data from an image source and projectsimages based on the acquired image data via the projection sections 35and 36 under the control of the control section 31. The image data usedby the projector 13 can be selected from image data input from the imagesource apparatus and image data stored in the storage section 32. Animage source of the projection image P3 projected by the projectionsection 35 and an image source of the projection image P4 projected bythe projection section 36 can be separately selected. The image sourceof the projection image P3 and the image source of the projection imageP4 may be different image sources or the same image source. Theprojector 13 has the function of swapping the image source of theprojection image P3 projected by the projection section 35 and the imagesource of the projection image P4 projected by the projection section 36based, for example, on the user's operation. The projector 13 can thusinterchange the projection images P3 and P4 being projected.

The projector 15 acquires image data from an image source and projectsan image based on the acquired image data via the projection section 55under the control of the control section 51. The image data used by theprojector 15 can be selected from image data input from the image sourceapparatus and image data stored in the storage section 52.

The projector 11 includes a position detecting section 27, which detectsposition input operation. The projector 11 allows the user to performposition input operation using a pointing element 201 on a projectionarea where the projection image P1 is projected.

The pointing element 201 is, for example, a pen-shaped device having astick-shaped shaft and used by an operator (user) who operates theprojector 11 with the pointing element 201 grasped by a hand. Theprojector 11 detects the position pointed with the front end of thepointing element 201 in a detection area set in the projection area ofthe projection image P1 as an operation position (pointed position).

The pointing element 201 in the present embodiment is a pen-shapedelement and may instead be a stick-shaped pointing element, such as apointing rod (not shown), or the operator's hand or finger may serve asthe pointing element. In the case where the operator's finger serves asthe pointing element, for example, a colored or patterned ring or a jighaving a shape that covers the operator's finger may be worn around thefinger. Still instead, the shape or motion of the operator's finger maybe identified by image recognition.

The position detecting section 27 (acceptance section) captures an imageof the detection area, extracts an image of the pointing element 201from the captured image, and determines the positional relationshipbetween the extracted image of the pointing element 201 and theprojection area where the projection image P1 is projected to detect theposition pointed by the user.

The projector 11 provides, for example, GUI (graphical user interface)operation on the basis of the position detected by the positiondetecting section 27. Further, the projector 11 carries out a drawingprocess of drawing a figure or any other object on the basis of theposition detected by the position detecting section 27. The projector 11superimposes the drawn image on the projection image P1 and projects thesuperimposed image. Specifically, the projector 11 superimposes thedrawn image on an image based on image data selected as the image sourceof the projection image P1 to produce a combined image and projects thecombined image as the projection image P1.

The projector 13 includes a position detecting section 37, which detectsposition input operation. The projector 13 allows the user to performposition input operation using a pointing element 203 on a projectionarea where the projection image P3 is projected.

The pointing element 203 is, for example, a pen-shaped device having astick-shaped shaft and used by a user who operates the projector 13 withthe pointing element 203 grasped by a hand, as in the case of thepointing element 201. The projector 13 detects the position pointed withthe front end of the pointing element 203 in a detection area set in theprojection area of the projection image P3 as an operation position(pointed position). The pointing element 203 is not limited to apen-shaped element and may instead be a stick-shaped pointing element,such as a pointing stick (not shown), or the operator's hand or fingermay serve as the pointing element. In the case where the operator'sfinger serves as the pointing element, for example, a colored orpatterned ring or a jig having a shape that covers the operator's fingermay be worn around the finger. Still instead, the shape or motion of theoperator's finger may be identified by image recognition.

The position detecting section 37 (acceptance section) captures an imageof the detection area, extracts an image of the pointing element 203from the captured image, and determines the positional relationshipbetween the extracted image of the pointing element 203 and theprojection area where the projection image P3 is projected to detect theposition pointed by the user.

The projector 13 provides, for example, GUI operation on the basis ofthe position detected by the position detecting section 37. Further, theprojector 13 carries out a drawing process of drawing a figure or anyother object on the basis of the position detected by the positiondetecting section 37. The projector 13 superimposes the drawn image onthe projection image P3 and project the superimposed image.Specifically, the projector 13 superimposes the drawn image on an imagebased on image data selected as the image source of the projection imageP3 to produce a combined image and projects the combined image as theprojection image P3.

In the projection system 1, the projection image P1 or the projectionimage P2 projected by the projector 11 can be projected by the projector13 or 15.

For example, to switch the projection image P3 to the projection imageP1, the projector 11 transmits control data that instructs projectionimage switching to the projector 13. The projector 11 subsequentlytransmits image data selected as the image source of the projectionimage P1 to the projector 13. The projector 13 receives the image datafrom the projector 11 and temporarily stores the received image data inthe storage section 32. The projector 13 selects the image datatemporarily stored in the storage section 32 as the image source of theprojection image P3. In a case where the image source of the projectionimage P1 is a still image, the projector 11 transmits the still imagedata to the projector 13 once. In a case where the image source of theprojection image P1 is motion images (video images), the projector 11continuously transmits the motion image data to the projector 13.Further, for example, the projector 11 may capture the image source ofthe projection image P1, produce still image data, and transmit thestill image data to the projector 13, and the projector 13 may selectthe still image data as the image source of the projection image P3 orP4.

Further, in the projection system 1, the projection image P3 or P4projected by the projector 13 can be projected by the projector 11 or15.

For example, to switch the projection image P1 to the projection imageP3, the projector 13 transmits control data that instructs projectionimage switching to the projector 11. Instead, the projector 11 maytransmit control data that instructs projection image switching to theprojector 13 to allow the projector 11 to project the projection imageP3 projected by the projector 13. The projector 13 subsequentlytransmits image data selected as the image source of the projectionimage P3 to the projector 11. The projector 11 receives the image datafrom the projector 13 and temporarily stores the received image data inthe storage section 22. The projector 13 selects the image datatemporarily stored in the storage section 22 as the image source of theprojection image P1. In a case where the image source of the projectionimage P3 is a still image, the projector 13 transmits the still imagedata to the projector 11 once. In a case where the image source of theprojection image P3 is motion images, the projector 13 continuouslytransmits the motion image data to the projector 11. Further, forexample, the projector 13 may capture the image source of the projectionimage P3, produce still image data, and transmit the still image data tothe projector 11, and the projector 11 may select the still image dataas the image source of the projection image P1 or P2.

Further, in the projection system 1, a combined image being projected bya projector can be transmitted to another projector. For example, in acase where the projector 11 is projecting a combined image, theprojector 11 may transmit data on the combined image to the projector 13or 15 and cause the projector 13 or 15 to project the combined image.Further, for example, in a case where the projector 13 is projecting acombined image, the projector 13 may transmit data on the combined imageto the projector 11 or 15 and cause the projector 11 or 15 to projectthe combined image.

A combined image projected by any of the projectors 11, 13, and 15 willnow be described. A combined image means an image that is a combinationof a plurality of images superimposed on each other, and the followingthree cases are presented by way of example.

A case 1 is a case where the projector 11 or 13 draws an image by usingan electronic blackboard function and combines the drawn image withanother image. In the case 1, the projector 11 or 13, when it performsthe electronic blackboard function, does not select an image sourcecorresponding to an external input but projects a background formed by acircuit system (control system) in the projector 11 or 13. A figure isdrawn in accordance with operation of the pointing element 201 in suchway that the figure is superimposed on the background. The backgroundis, for example, an all-white screen (entirely white or gray screen) oran all-white screen with ruler lines. The projector 11 or 13 may store abackground image template in the storage section 22 or 32 and use thetemplate to project the background. The template may be background imagedata itself or may be a program or data for producing background imagedata.

A case 2 is a case where the projector 11 or 13 projects an image froman external image source and further projects a line or a figure drawnwith the pointing element 201 and superimposed on the image. In thiscase, usability that allows a desired object to be added to the imageoutputted from the external source (image source apparatus) can beachieved. For example, a PC as the image source apparatus inputs ananalog signal carrying a presentation material to the projector 11 viaan analog RGB cable (not shown). In this example, the user operates thepointing element 201 to draw a bright marking in the presentationmaterial, for example, on a graph and at a portion thereof that the userdesires to highlight, and the marking and the presentation material areso projected that the marking is superimposed on the presentationmaterial. In the case 2, a document camera or any other external imagingdevice may be used as the external source.

A case 3 is a case where a non-electronic diagrammatic picture, such asa map or a large-format teaching material, is presented on any of theflat surfaces PL and the projection screen of any of the projectors 11,13, and 15 is superimposed on the diagrammatic picture. In the case 3, adiagrammatic picture of an actual object is placed on any of the flatsurfaces PL1, PL2, PL3, and other surfaces, and the projection image issuperimposed on the diagrammatic picture. Any of the projectors 11, 13,and 15 can therefore perform the action in the case 3. The color orcontent of the diagrammatic picture of an actual object presented in thecase 3 is not limited to a specific color or content, and not only a mapin typical colors, a blank map, or any other drawing but a typicaldocument, presentation material, and other pieces of information can beused. Further, in a case where an actual blackboard or white board isinstalled on any of the flat surfaces PL1, PL2, PL3, and other surfaces,the combined image in the case 3 may include a projection imagesuperimposed on a figure, a sentence, a picture, or any other objectdrawn on the blackboard or the white board. A non-electronicdiagrammatic picture of an actual object presented in the case 3 isimaged by an imaging section 28 or 38. The imaging section 28 is animaging section that images the portion within a viewing angle differentfrom that of an imaging section 273 (FIG. 4), which detects the positionof the pointing element 201. The imaging section 28 images the portionwithin a viewing angle containing a projection image projected by theprojection section 25 and/or the projection section 26. The imagingsection 38 provided in the projector 13 is the same as the imagingsection 28 of the projector 11. That is, the imaging section 38 is animaging section that images the portion within a viewing angle differentfrom that of an imaging section 373 (FIG. 6), which detects the positionof a pointing element 302. In more detail, the imaging section 38 is animaging section that images the portion within a viewing anglecontaining a projection image projected by the projection section 35and/or the projection section 36.

For example, consider a case where the imaging section 28 images theflat surface PL1, a diagrammatic picture of an actual object is placedon the flat surface PL1, and the projector 11 projects the projectionimage P1 on the diagrammatic picture. An image captured with the imagingsection 28 contains the projection image P1 superimposed on thediagrammatic picture of the actual object. That is, image data on thestate in which the projection image P1 is superimposed on thediagrammatic picture of the actual object can be produced. Similarly,for example, consider a case where the imaging section 38 images theflat surface PL2, a diagrammatic picture of an actual object is placedon the flat surface PL2, and the projector 13 projects the projectionimage P3 on the diagrammatic picture. An image captured with the imagingsection 38 contains the projection image P3 superimposed on thediagrammatic picture of the actual object. That is, image data on thestate in which the projection image P3 is superimposed on thediagrammatic picture of the actual object can be produced.

As described with reference to the cases 1, 2, and 3, the projectors 11,13, and 15, which form the projection system 1, can not only project asingle image but show the user a combined image that is the combinationof a plurality of images.

In a case where the projector 11 performs the action in the case 1 toproject a combined image, the image data is stored in a storage area ofthe control system (DRAM 225 (FIG. 4), for example) of the projector 11.The DRAM 225 separately stores the background image data and data on theline and figure drawn by operation of the pointing element 201.Specifically, data on the background and data on each of the line andthe figure (called constituent parts) drawn by the pointing element 201is stored in the form of vector data or raster image data. Image data onthe combined image that is the combination of the sets of data describedabove is formed in a frame memory 241 (FIG. 4). In the case 1, toextract the image data on the combined image from the projector 11,there is a method for extracting component data on the constituent partsstored in the DRAM 225. To transmit the data from the projector 11 toanother projector (projector 13, for example) in accordance with themethod, the component data on the constituent parts stored in the DRAM225 may be transmitted to the projector 13, and the projector 13 mayreconfigure the image data on the combined image in a frame memory 341.It is instead conceivable to employ a method in which the projector 11may capture the data on the combined image in the frame memory 241 andtransmit the captured data as image data to the projector 13. The sameholds true for a case where the projector 13 projects a combined image.

In the case 2, externally input image data or image data that is anexternally input analog signal having undergone digital conversion isstored in the storage area of the control system (DRAM 225, for example)of the projector 11. The DRAM 225 separately stores the image data froman external source and the data on the line and figure drawn byoperation of the pointing element 201. Image data on a combined imagethat is the combination of the image data and the line/figure data isformed in the frame memory 241. When the image data from the externalsource has changed and the image data on the combined image in the framememory 241 is changed accordingly, for example, the changed image datamay be stored in another storage area of the frame memory 241. The imagedata on the combined image before the change held in the frame memory241 allows restoration of the projection image before the change.

In the case 2, to extract the image data on the combined image from theprojector 11, there is a method for extracting component data on theconstituent parts stored in the DRAM 225. To transmit the data from theprojector 11 to another projector (projector 13, for example) inaccordance with the method, the component data on the constituent partsstored in the DRAM 225 and the image data that forms the background aretransmitted to the projector 13. The projector 13 may then reconfigurethe image data on the combined image in the frame memory 341. It isinstead conceivable to employ a method for capturing the data on thecombined image in the frame memory 241 and transmitting the captureddata as image data to the projector 13. The same holds true for the casewhere the projector 13 projects a combined image.

A combined image projected in the case 3 is an image that is thecombination of an actual object and a projection image. In theprojection system 1, when a projector projects a combined image in thecase 3, the combined image can be transmitted to another projector.

That is, when the projector 11 projects a combined image in the case 3,the projector 11 causes the imaging section 28 to image the actualobject, which forms the base on which the projection image issuperimposed. In this case, it is more preferable that only at theinstant of the imaging, the projector 11 causes the projection section25 or 26 to stop projecting light or blocks the light projected by theprojection section 25 or 26 so that only the base is imaged. Theprojector 11 captures data representing the image so projected as to besuperimposed on the base from the frame memory 241. The projector 11 maythen transmit the data representing the image captured with the imagingsection 28 and the data captured from the frame memory 241 as data onthe combined image to another projector, such as the projector 13 or 15.

In the projection system 1, any of the projectors 11, 13, and 15 can beset as the apparatus that transmits the control data that instructs theprojection image switching. It can be said that the thus set apparatusis a primary-control-side projector. For example, in a case where theprojector 11 is set as the primary-control-side projector, the projector11 transmits the control data to control the image switching between theprojectors 11 and 13, between the projectors 11 and 15, and between theprojectors 13 and 15. Further, in this case, the projector 11 may beconfigured to control swapping of the projection images P3 and P4projected by the projector 13 by transmitting the control data to theprojector 13.

The aspect of the projection image swapping is not limited to the casewhere a projection image projected by a projector is projected byanother projector and may be an aspect in which two projection imagesare swapped. For example, to swap the projection image P1 and theprojection image P3, the projector 11 transmits image data selected asthe image source of the projection image P1 to the projector 13. Theprojector 13 transmits image data selected as the image source of theprojection image P3 to the projector 11. The projectors 11 and 13 eachselect the received image data as the image source.

In the cases 1, 2, and 3 described above, to cause a combined imagetransmitted by the projector 11 to another projector, the projector 13or 15, to be projected via the projection section 25 again, theprojector 11 may re-acquire the image data on the combined image fromthe projector 13 or 15. That is, the projector 13 or 15 may transmit theimage data to the projector 11. Instead, the projector 11 may store theimage data to be transmitted to another projector, the projector 13 or15, in the storage section 22 when the projector 11 transmits the imagedata, and the projector 11 may reuse and project the image data storedin the storage section 22.

Further, in the case 3, to cause a combined image that the projector 11projects via the projection section 26 or transmits to anotherprojector, the projector 13 or 15, to be projected via the projectionsection 25 again, the projection section 25 may be configured to projectimage data containing no image data captured by the imaging section 28.Instead, image data containing the image data captured by the imagingsection 28 may be projected so that the combined image can be reproducedeven after the actual object, which forms the base, is removed. Stillinstead, either of the two types of image data may be selected andprojected.

The configurations of the projectors 11, 13, and 15, which form theprojection system 1, will subsequently be described in detail.

FIG. 4 is a block diagram of the projector 11.

The projector 11 includes the control section 21, the storage section22, the wireless communication section 23, the image processing section24, the projection sections 25 and 26, and the position detectingsection 27, as described above. The projector 11 further includes alight source driving section 235, a light modulator driving section 236,an image interface (I/F) section 243, an interface section 245, an inputprocessing section 247, and a voice processing section 281. The sectionsdescribed above are connected to each other via a bus 280. Further, theframe memory 241 is connected to the image processing section 24, and anoperation panel 285 and a remote control light receiving section 287 areconnected to the input processing section 247, as will be describedlater. A loudspeaker 282 is connected to the voice processing section281.

The image interface section 243 (first acquisition section, secondacquisition section) is an interface that connects the image sourceapparatus described above to the projector 11 and includes a connector,an interface circuit, and other components. The image interface section243 may include a connector to which a card-shaped recording medium,such as an SD (secure digital) memory card, a USB memory device, or anyother portable storage medium can be connected, and an interfacecircuit.

The image interface section 243 is not limited to the configuration inwhich it is wired to the image source apparatus. For example, the imageinterface section 243 may be configured to perform wireless datacommunication that complies with a wireless LAN (including Wi-Fi),Miracast (registered trademark), Bluetooth (registered trademark), orany other standard with the image source apparatus.

Digital image data in a data format that can be processed by theprojector 11 is input to the image interface section 243. The digitalimage data may be still image data or motion image data. In thefollowing description, data input from the image source apparatus to theimage interface section 243 is called input image data OS1.

The image interface section 243 is not limited to an interface to whichdigital image data can be input and may, for example, have aconfiguration to which an analog image (video) signal can be input. Inthis case, the input image data OS1 may be an analog signal. In thiscase, the image interface section 243 may have the function ofconverting an analog signal into digital data.

The interface section 245 is connected to an external apparatus, such asa PC, and transmits and receives a variety of data, such as the controldata, to and from the external apparatus. For example, the interfacesection 245 performs data communication that complies with Ethernet(registered trademark), IEEE 1394, USB (universal serial bus), or anyother standard.

The projection section 25 includes a light source 251, a light modulator252, which modulates light emitted from the light source 251 to produceimage light, and a projection system 253, which projects the modulatedimage light from the light modulator 252 to form a projection image.

The projection section 26 includes a light source 261, a light modulator262, which modulates light emitted from the light source 261 to produceimage light, and a projection system 263, which projects the modulatedimage light from the light modulator 262 to form a projection image.

The light sources 251 and 261 are each formed of a halogen lamp, a xenonlamp, an ultrahigh-pressure mercury lamp, or any other lamp or an LED, alaser light source, or any other solid-state light source. The lightsources 251 and 261 are each turned on by using electric power suppliedfrom the light source driving section 235 and emit light toward thelight modulators 252 and 262, respectively. The light sources 251 and261 do not necessarily have the same configuration. For example, thelight source 251 may be formed of an ultrahigh-pressure mercury lamp,and the light source 261 may be formed of a solid-state light source.

The light source driving section 235 can turn on and off the lightsources 251 and 261 individually. The light source driving section 235may be configured to adjust the luminance of the light emitted from thelight sources 251 and 261 individually under the control of the controlsection 21.

The light modulator 252 modulates the light emitted from the lightsource 251 to produce image light and irradiates the projection system253 with the image light. The light modulator 262 modulates the lightemitted from the light source 261 to produce image light and irradiatesthe projection system 263 with the image light.

The light modulators 252 and 262 each include, for example, atransmissive liquid crystal light valve, a reflective liquid crystallight valve, a digital mirror device (DMD), or any other lightmodulating element. The light modulators 252 and 262 do not necessarilyhave the same configuration. For example, the light modulator 252 may beformed of a transmissive liquid crystal light valve, and the lightmodulator 262 may be formed of a reflective liquid crystal light valve.The light modulator driving section 236 is connected to the lightmodulating elements of the light modulators 252 and 262. The lightmodulator driving section 236 drives the light modulators 252 and 262 onthe basis of image signals outputted from the image processing section24. The light modulator driving section 236 can separately drive thelight modulators 252 and 262 under the control of the control section21. The light modulator driving section 236 drives the light modulatingelement of each of the light modulators 252 and 262 to set the grayscaleof each pixel so that an image is drawn on a frame (screen) basis in thelight modulating element.

The projector 11 has a configuration in which the single light modulatordriving section 236 drives the light modulators 252 and 262 as anexample of the configuration in which the single projector 11 canproject a plurality of projection images P1 and P2. The aboveconfiguration is only one example, and, for example, the projector 11may instead include two light modulator driving sections 236; one of thelight modulator driving sections 236 may drive the light modulator 252,and the other light modulator driving section 236 may drive the lightmodulator 262.

The image processing section 24 inputs an image signal representing animage to be drawn in the light modulator 252 and an image signalrepresenting an image to be drawn in the light modulator 262 to thelight modulator driving section 236. Specifically, a plurality of signallines via which the image processing section 24 inputs the image signalsto the light modulator driving section 236 may be provided. Instead, theimage processing section 24 may input the image signal representing animage to be drawn in the light modulator 252 and the image signalrepresenting an image to be drawn in the light modulator 262 in a timedivision manner to the light modulator driving section 236.

The projection system 253 includes a lens and a mirror that focus thelight modulated by the light modulator 252 on a screen. The projectionsystem 253 may further include a zoom lens, a focus lens, and a varietyof other lenses or lens groups. The projection system 263 similarlyincludes a lens and a mirror that focus the light modulated by the lightmodulator 262 on a screen and may further include a zoom lens, a focuslens, and a variety of other lenses or lens groups. In the presentembodiment, the projection system 253 is so disposed as to face the flatsurface PL1, and the projection system. 263 is so disposed as to facethe flat surface PL4. The projection section 25 projects the image lightL1 toward the flat surface PL1 to project the projection image P1, andthe projection section 26 projects the image light L2 toward the flatsurface PL4 to project the projection image P2. The image light L1 andthe image light L2 are projected in directions in which the image lightL1 and the image light L2 do not overlap with each other. The imagelight L1 and the image light L2 do not overlap with each other at leastunless the distance from the projector 11 is greater than the distanceover which the image light L1 travels to the flat surface PL1 or thedistance over which the image light L2 travels to the flat surface PL4.

The position detecting section 27 includes an imaging section 273, atarget detecting section 272, and a coordinate calculating section 271.The imaging section 273 is a digital camera that images a rangecontaining the detection area where operation of the pointing element201 can be detected, and the imaging section 273 produces captured imagedata. The imaging range, that is, the viewing angle of the imagingsection 273 covers at least the detection area. The imaging section 273is not limited to a camera that images visible light and may be a camerathat images infrared light.

The target detecting section 272 detects an image of the pointingelement 201 from the image data captured by the imaging section 273.That is, the target detecting section 272 analyzes the image datacaptured by the imaging section 273 to detect an image of the pointingelement 201 from the captured image. In a case where the captured imagecontains an image of the pointing element 201, the target detectingsection 272 identifies the position of the front end of the pointingelement 201 in the image thereof as the operation position. The targetdetecting section 272 determines the coordinates representing theposition of the front end of the pointing element 201 in the capturedimage.

The coordinate calculating section 271 converts the coordinates of theposition of the front end of the pointing element 201 that have beendetected and identified by the target detecting section 272 from thecaptured image into the coordinates in the detection area, whereoperation of the pointing element 201 is detected. The coordinatecalculating section 271 outputs the calculated coordinates as coordinatedata on a pointed position in the detection area to the control section21.

The input processing section 247 (acceptance section) accepts the user'soperation.

The input processing section 247 detects operation performed on theoperation panel 285. The operation panel 285 is disposed, for example,on the enclosure of the projector 11 and includes a variety of switches.The input processing section 247 detects operation performed on any ofthe switches on the operation panel 285 and outputs control datarepresenting the operated switch to the control section 21.

The remote control light receiving section 287, which is connected tothe input processing section 247, receives an infrared signaltransmitted from a remote control 20 and decodes the received signal.The remote control 20 includes a variety of switches and transmits aninfrared signal representing an operated switch. The remote controllight receiving section 287 decodes the received signal and outputs dataon the decoded signal to the input processing section 247. The inputprocessing section 247 outputs the data input from the remote controllight receiving section 287 to the control section 21.

The control section 21 (switching control section, first controlsection) is, for example, a processor including a CPU (centralprocessing unit), a flash ROM, and a RAM (random access memory) that arenot shown. The control section 21, in which the CPU executes a programstored in the flash ROM or the storage section 22, controls each portionof the projector 11. The control section 21 includes a projectioncontrol section 211, a drawing control section 212, an operationacquiring section 213, and a communication control section 214 asfunctional blocks that control the portions of the projector 11. Thefunctional blocks are achieved by cooperation between software andhardware when the CPU of the control section 21 executes the program.

The projection control section 211 controls the image processing section24, the light source driving section 235, the light modulator drivingsection 236, and other portions to control the projection of theprojection images P1 and P2 performed by the projector 11. Theprojection control section 211 controls the timing when a processcarried out by the image processing section 24 is carried out, acondition under which the process is carried out, and other factorsassociated with the process. The projection control section 211 furthercontrols the light source driving section 235 to, for example, adjustthe luminance of the light emitted from the light sources 251 and 261.

The projection control section 211 selects an image source of theprojection image P1 and an image source of the projection image P2 onthe basis of the user's operation acquired by the operation acquiringsection 213. The projection control section 211 controls the imageprocessing section 24 to cause it to acquire image data from each of theselected image sources.

The projection control section 211 further performs projection imageswitching control in which the projection image P1 or P2 is switched tothe projection image P3 or P4 projected by the projector 13. In thiscase, the projection control section 211 changes the image source of theprojection image P1 or P2 to the image data transmitted from theprojector 13 and temporarily stored in the storage section 22.

The projection control section 211 further causes the projector 13 or 15to project the projection image P1 or P2. In this case, the projectioncontrol section 211 produces control data that controls the projector 13or 15 and transmits the control data under the control of thecommunication control section 214. The projection control section 211further transmits the image data on the projection image P1 or P2 orcombined image data stored in the storage section 22 under the controlof the communication control section 214.

The projection control section 211 further controls the imaging section28 to cause it to perform imaging to acquire captured image data. Theprojection control section 211 may perform projection by using theacquired captured image data as the image source. The projection controlsection 211 may instead temporarily store the captured image data fromthe imaging section 28 in the DRAM 225 and, for example, transmit thecaptured image data to another projector.

The drawing control section 212 draws a figure (including straight line,curved line, geometric figure, and other objects), an image, a letter,and any other symbol on the basis of the coordinates of the pointedposition detected by the position detecting section 27. The drawingcontrol section 212 produces image data on a figure corresponding to thecoordinates of pointed positions detected by the position detectingsection 27 or the trajectory of the coordinates and causes the imageprocessing section 24 to combine the produced image data with an imagedrawn in the frame memory 241. The image processing section 24 mayinstead carry out the process of producing the image data on the figure.

The operation acquiring section 213 detects operation performed on theprojector 11. The operation acquiring section 213 detects operationperformed via the remote control 20 and the operation panel 285, whichfunction as input devices, on the basis of data input from the inputprocessing section 247.

In a state in which the image processing section 24 and the projectionsection 25 project an image for GUI operation on the basis of GUI data222, the operation acquiring section 213 acquires the position pointedwith the pointing element 201 from the position detecting section 27 toidentify the content of GUI operation. The image for GUI operation is,for example, a menu bar 206 (FIG. 7), which will be described later. Ina case where operation of the pointing element 201 is detected and theposition pointed with the pointing element 201 falls within the menu bar206, the operation acquiring section 213 identifies an icon specified inthe menu bar 206 and determines the content of the operation.

The storage section 22 is a storage device that stores data processed bythe control section 21 and the program executed by the CPU of thecontrol section 21. The storage section 22 can be configured to includea variety of volatile storage devices and/or nonvolatile storagedevices. In the present embodiment, the storage section 22 includes aflash ROM 220 and the DRAM (dynamic RAM) 225. The flash ROM 220 isadvantageous in that it is a rewritable nonvolatile storage device, andthe DRAM 225 is advantageous in that the access speed thereof is fasterthan that of the flash ROM 220. The flash ROM 220 is formed of anonvolatile semiconductor storage element and stores setting data 221and the GUI data 222. The DRAM 225 stores content data 223 andprojection image data 224. The control section 21 and other functionalsections can therefore read the content data 223 and the projectionimage data 224 at high speed. When the projector 11 is powered off, thecontent data 223 and the projection image data 224 may be saved in theflash ROM 220. The DRAM 225 may be replaced with a nonvolatile memory.

The setting data 221 contains a variety of setting values (parameters)that specify actions of the projector 11. The setting data 221 contains,for example, setting values that allow the projector 11 to performwireless data communication over the communication network 10.Specifically, the setting data 211 may contain identificationinformation, such as the network addresses and the IDs of the projectors11, 13, and 15 and the wireless communication apparatus 9, andauthentication information, such as pass phrases thereof. The settingdata 221 may further contain data that specifies the type or content ofimage processing performed by the image processing section 24 andparameters used in the image processing.

The GUI data 222 (image data for operation) contains data for operationof the projector 11 via a GUI. The projector 11, which projects theimage for operation via the projection section 25 and detects operationperformed on the projected image, allows operation via the GUI. The GUIdata 222 contains image data on the GUI-forming image for operation anddata for detecting operation performed on the image data.

The content data 223 contains still image data or motion image data thatcan be selected as an image source. The content data 223 may containvoice data.

The projection image data 224 contains image data on an image projectedby the projector 11 via the projection section 25 or 26. For example, tocapture the projection image under the control of the control section21, the image processing section 24 acquires the image data representingthe image drawn in the frame memory 241 and stores the image data as theprojection image data 224. In a case where the projector 11 receivesimage data on a projection image from the projector 13 or 15, thereceived image data is stored as the projection image data 224. In acase where the drawing control section 212 draws an image in accordancewith operation of the pointing element 201, and the image processingsection 24 produces a combined image containing the drawn image,followed by projection of the combined image via the projection section25, image data on the projected combined image is temporarily stored asthe projection image data 224.

The frame memory 241 is connected to the image processing section 24.

The image processing section 24 acquires image data from an image sourceselected under the control of the control section 21 and performs avariety of types of image processing on the acquired image data. Forexample, the image processing section 24 carries out a resolutionconversion process of converting the resolution of the image data inaccordance with the display resolution of the light modulators 252 and262. The image processing section 24 further carries out a geometriccorrection process of correcting the shape of the image, a color tonecorrection process of correcting the color tone of the image data, andother processes. The image processing section 24 can further performimage processing that rotates the orientation of an image projected bythe projection section 26 by 180 degrees under the control of thecontrol section 21. The image processing section 24 produces an imagesignal for displaying the processed image data and outputs the imagesignal to the light modulator driving section 236.

To perform image processing, the image processing section 24 (imageproducing section) develops an image based on image data acquired froman image source in the frame memory 241 and performs a variety of typesof processing on the image developed in the frame memory 241. Forexample, the image processing section 24 superimposes an image drawn byoperation of the pointing element 201 on the image in the frame memory241 so that the two images are combined with each other to produce acombined image (superimposed image) under the control of the drawingcontrol section 212. To display an image for GUI operation, such as themenu bar 206 (FIG. 7), the image processing section 24 superimposes animage based on the GUI data 222 on the image in the frame memory 241 sothat the two images are combined with each other to produce a combinedimage. The image processing section 24 may output image data on thecombined image combined in the frame memory 241 to the storage section22 and cause the storage section 22 to store the image data as theprojection image data 224. In a case where the projection controlsection 211 instructs the image processing section 24 to capture theprojection image, the image processing section 24 may output the imagedata in the frame memory 241 to the storage section 22 and cause thestorage section 22 to store the image data as the projection image data224.

In the present embodiment, the single image processing section 24processes the projection image P1 and the projection image P2. In thiscase, the frame memory 241 may be configured to have an area where animage to be projected by the projection section 25 is developed and anarea where an image to be projected by the projection section 26 isdeveloped.

The light source driving section 235 supplies each of the light sources251 and 252 with drive current and pulses to cause the light sources 251and 252 to emit light. The light source driving section 235 may becapable of adjusting the luminance of the light emitted from the lightsources 251 and 252. The light modulator driving section 236 drives thelight modulators 252 and 262 on the basis of image signals input fromthe image processing section 24 to draw images in the light modulators252 and 262 on a frame basis under the control of the control section21.

The voice processing section 281 outputs voice via the loudspeaker 282on the basis of input digital voice data or an input analog voice signalunder the control of the control section 21.

FIG. 5 is a block diagram of the projector 13.

The projector 13 includes the control section 31, the storage section32, the wireless communication section 33, the image processing section34, the projection sections 35 and 36, and the position detectingsection 37, as described above. The projector 13 further includes alight source driving section 335, a light modulator driving section 336,an image interface section 343, an interface section 345, an inputprocessing section 347, a switching section 361, and a voice processingsection 381. The sections described above are connected to each othervia a bus 380. Further, the frame memory 341 is connected to the imageprocessing section 34, and an operation panel 385 and a remote controllight receiving section 387 are connected to the input processingsection 347, as will be described later. A loudspeaker 382 is connectedto the voice processing section 381.

The image interface section 343 (first acquisition section, secondacquisition section) is an interface that connects the image sourceapparatus described above to the projector 13 and includes a connector,an interface circuit, and other components. The image interface section343 may include a connector to which a card-shaped recording medium,such as an SD memory card, a USB memory device, or any other portablestorage medium can be connected, and an interface circuit.

The image interface section 343 is not limited to the configuration inwhich it is wired to the image source apparatus. For example, the imageinterface section 343 may be configured to perform wireless datacommunication that complies with a wireless LAN (including Wi-Fi),Miracast (registered trademark), Bluetooth (registered trademark), orany other standard with the image source apparatus.

Digital image data in a data format that can be processed by theprojector 13 is input to the image interface section 343. The digitalimage data may be still image data or motion image data. In thefollowing description, data input from the image source apparatus to theimage interface section 343 is called input image data OS2.

The image interface section 343 is not limited to an interface to whichdigital image data can be input and may, for example, have aconfiguration to which an analog image (video) signal can be input. Inthis case, the input image data OS2 may be an analog signal. In thiscase, the image interface section 343 may have the function ofconverting an analog signal into digital data.

The interface section 345 is connected to an external apparatus, such asa PC, and transmits and receives a variety of data, such as the controldata, to and from the external apparatus. For example, the interfacesection 345 performs data communication that complies with Ethernet,IEEE 1394, USB, or any other standard.

The projector 13 includes alight source 351, alight modulator 352, whichmodulates light emitted from the light source 351 to produce imagelight, projection systems 362 and 363, and a direction switching section353, which switches the path of the modulated image light from the lightmodulator 352 to another and guides the image light along the switchedpath. That is, the projector 13 has a configuration in which thedirection switching section 353 guises the image light to the twoprojection systems 362 and 363 as an example of the configuration inwhich the single projector 13 can project a plurality of projectionimages P3 and P4.

The direction switching section 353 can switch a state in which themodulated image light from the light modulator 352 is guided to theprojection system 362 and projected on the flat surface PL2 to a statein which the modulated image light from the light modulator 352 isguided to the projection system 363 and projected on the flat surfacePL4 and vice versa. In the configuration described above, the projectionsystem. 362 forms the projection section 35, and the projection system363 forms the projection section 36.

The timing when the state in which the direction switching section 353guides the image light to the projection system 362 is switched to thestate in which the direction switching section 353 guides the imagelight to the projection system 363 and vice versa can be controlled bythe control section 21. The control section 21 changes the image drawnin the light modulator 352 in synchronization with the timing when thedirection switching section 353 performs the switching to allow theprojector 13 to project different images via the projection systems 362and 363. That is, the projector 13, which is configured to use thesingle light modulator 352, can project two different projection imagesin different directions.

In the present embodiment, the projection system 362 is so disposed asto face the flat surface PL2, and the projection system 363 is sodisposed as to face the flat surface PL4. The projection section 35projects the image light L3 toward the flat surface PL3 to project theprojection image P3, and the projection section 36 projects the imagelight L4 toward the flat surface PL4 to project the projection image P4.The image light L3 and the image light L4 are projected in directions inwhich the image light L3 and the image light L4 do not overlap with eachother. The image light L3 and the image light L4 do not overlap witheach other at least unless the distance from the projector 13 is greaterthan the distance over which the image light L3 travels to the flatsurface PL2 or the distance over which the image light L4 travels to theflat surface PL4.

The light source 351 is formed of a halogen lamp, a xenon lamp, anultrahigh-pressure mercury lamp, or any other lamp or an LED, a laserlight source, or any other solid-state light source. The light source351 is turned on by using electric power supplied from the light sourcedriving section 335 and emits light toward the light modulator 352.

The light modulator 352 modulates the light emitted from the lightsource 351 to produce image light and irradiates the projection systems362 and 363 with the image light.

The light modulator 352 includes, for example, a transmissive liquidcrystal light valve, a reflective liquid crystal light valve, a digitalmirror device, or any other light modulating element. The lightmodulator driving section 336 is connected to the light modulatingelement of the light modulator 352. The light modulator driving section336 drives the light modulator 352 on the basis of an image signaloutputted from the image processing section 34. The light modulatordriving section 336 drives the light modulating element of the lightmodulator 352 to set the grayscale of each pixel so that an image isdrawn on a frame (screen) basis in the light modulating element.

The projection system 362 includes a lens and a mirror that focus thelight modulated by the light modulator 352 on a screen. The projectionsystem 362 may further include a zoom lens, a focus lens, and a varietyof other lenses or lens groups. The projection system 363 similarlyincludes a lens and a mirror that focus the light modulated by the lightmodulator 352 on a screen and may further include a zoom lens, a focuslens, and a variety of other lenses or lens groups.

The position detecting section 37 includes a coordinate calculatingsection 371, a target detecting section 372, and an imaging section 373.The imaging section 373 is a digital camera that images a rangecontaining the detection area where operation of the pointing element203 can be detected, and the imaging section 373 produces captured imagedata. The imaging range, that is, the viewing angle of the imagingsection 373 covers at least the detection area. The imaging section 373is not limited to a camera that images visible light and may be a camerathat images infrared light.

The target detecting section 372 detects an image of the pointingelement 203 from the image data captured by the imaging section 373.That is, the target detecting section 372 analyzes the image datacaptured by the imaging section 373 to detect an image of the pointingelement 203 from the captured image. In a case where the captured imagecontains an image of the pointing element 203, the target detectingsection 372 identifies the position of the front end of the pointingelement 203 in the image thereof as the operation position. The targetdetecting section 372 determines the coordinates representing theposition of the front end of the pointing element 203 in the capturedimage.

The coordinate calculating section 371 converts the coordinates of theposition of the front end of the pointing element 203 that have beendetected and identified by the target detecting section 372 from thecaptured image into the coordinates in the detection area, whereoperation of the pointing element 203 is detected. The coordinatecalculating section 371 outputs the calculated coordinates as coordinatedata on a pointed position in the detection area to the control section31.

The input processing section 347 (acceptance section) accepts the user'soperation.

The input processing section 347 detects operation performed on theoperation panel 385. The operation panel 385 is disposed, for example,on the enclosure of the projector 13 and includes a variety of switches.The input processing section 347 detects operation performed on any ofthe switches on the operation panel 385 and outputs control datarepresenting the operated switch to the control section 31.

The remote control light receiving section 387, which is connected tothe input processing section 347, receives an infrared signaltransmitted from a remote control 30 and decodes the received signal.The remote control 30 includes a variety of switches and transmits aninfrared signal representing an operated switch. The remote controllight receiving section 387 decodes the received signal and outputs dataon the decoded signal to the input processing section 347. The inputprocessing section 347 outputs the data input from the remote controllight receiving section 387 to the control section 31.

The control section 31 (switching control section, first controlsection) includes, for example, a CPU, a flash ROM, and a RAM that arenot shown. The control section 31, in which the CPU executes a programstored in the flash ROM or the storage section 32, controls each portionof the projector 13. The control section 31 includes a projectioncontrol section 311, a drawing control section 312, an operationacquiring section 313, and a communication control section 314 asfunctional blocks that control the portions of the projector 13. Thefunctional blocks are achieved by cooperation between software andhardware when the CPU of the control section 31 executes the program.

The projection control section 311 controls the image processing section34, the light source driving section 335, the light modulator drivingsection 336, and other portions to control the projection of theprojection images P3 and P4 performed by the projector 13. Theprojection control section 311 controls the timing when a processcarried out by the image processing section 34 is carried out, acondition under which the process is carried out, and other factorsassociated with the process. The projection control section 311 furthercontrols the light source driving section 335 to, for example, adjustthe luminance of the light emitted from the light source 351.

The projection control section 311 selects an image source of theprojection image P3 and an image source of the projection image P4 onthe basis of the user's operation acquired by the operation acquiringsection 313. The projection control section 311 controls the imageprocessing section 34 to cause it to acquire image data from each of theselected image sources.

The projection control section 311 further performs projection imageswitching control in which the projection image P3 or P4 is switched tothe projection image P1 or P2 projected by the projector 11. In thiscase, the projection control section 311 changes the image source of theprojection image P3 or P4 to the image data transmitted from theprojector 11 and temporarily stored in the storage section 32.

The projection control section 311 further causes the projector 11 or 15to project the projection image P3 or P4. In this case, the projectioncontrol section 311 produces control data that controls the projector 11or 15 and transmits the control data under the control of thecommunication control section 314. The projection control section 311further transmits the image data on the projection image P3 or P4 orcombined image data stored in the storage section 32 under the controlof the communication control section 314.

The projection control section 311 further controls the imaging section38 to cause it to perform imaging to acquire captured image data. Theprojection control section 311 may perform projection by using theacquired captured image data as the image source. The projection controlsection 311 may instead temporarily store the captured image data fromthe imaging section 38 in a DRAM 325 and, for example, transmit thecaptured image data to another projector.

The drawing control section 312 draws a figure (including straight line,curved line, geometric figure, and other objects), an image, a letter,and any other symbol on the basis of the coordinates of the pointedposition detected by the position detecting section 37. The drawingcontrol section 312 produces image data on a figure corresponding to thecoordinates of pointed positions detected by the position detectingsection 37 or the tracing of the coordinates and causes the imageprocessing section 34 to combine the produced image data with an imagedrawn in the frame memory 341. The image processing section 34 mayinstead carry out the process of producing the image data on the figure.

The operation acquiring section 313 detects operation performed on theprojector 13. The operation acquiring section 313 detects operationperformed via the remote control 30 and the operation panel 385, whichfunction as input devices, on the basis of data input from the inputprocessing section 347.

In a state in which the projection section 35 (projection system 362)projects an image for GUI operation on the basis of GUI data 322, theoperation acquiring section 313 acquires the position pointed with thepointing element 203 from the position detecting section 37 to identifythe content of GUI operation. The image for GUI operation is, forexample, the menu bar 206 (FIG. 7). In a case where the position pointedwith the pointing element 203 falls within the image for GUI operation,the operation acquiring section 313 identifies an icon or any otherobject specified in the image for GUI operation and determines thecontent of the operation.

The storage section 32 is a storage device that stores data processed bythe control section 31 and the program executed by the CPU of thecontrol section 31. The storage section 32 can be configured to includea variety of volatile storage devices and/or nonvolatile storagedevices. In the present embodiment, the storage section 32 includes aflash ROM 320 and the DRAM 325. The flash ROM 320 is configured in thesame manner as the flash ROM 220, and the DRAM 325 is configured in thesame manner as the DRAM 225. The flash ROM 320 stores setting data 321and the GUI data 322, and the DRAM 325 stores content data 323 andprojection image data 324. When the projector 13 is powered off, thecontent data 323 and the projection image data 324 may be saved in theflash ROM 320.

The setting data 321 contains a variety of setting values (parameters)that specify actions of the projector 13. The setting data 321 contains,for example, setting values that allow the projector 13 to performwireless data communication over the communication network 10.Specifically, the setting data 311 contains identification information,such as the network addresses and the IDs of the projectors 11, 13, andand the wireless communication apparatus 9, and authenticationinformation, such as pass phrases thereof. The setting data 321 mayfurther contain data that specifies the type or content of imageprocessing performed by the image processing section 34 and parametersused in the image processing.

The GUI data 322 (image data for operation) contains data for operationof the projector 13 via a GUI. The projector 13, which projects theimage for operation via the projection section 35 and detects operationperformed on the projected image, allows operation via the GUI. The GUIdata 322 contains image data on the GUI-forming image for operation anddata for detecting operation performed on the image data.

The content data 323 contains still image data or motion image data thatcan be selected as an image source. The content data 323 may containvoice data.

The projection image data 324 contains image data on an image projectedby the projector 13 via the projection section 35 or 36. For example, tocapture the projection image under the control of the control section31, the image processing section 34 acquires the image data representingthe image drawn in the frame memory 341 and stores the image data as theprojection image data 324. In a case where the projector 13 receivesimage data on a projection image from the projector 11 or 15, thereceived image data is stored as the projection image data 324. In acase where the drawing control section 312 draws an image in accordancewith operation of the pointing element 203, and the image processingsection 34 produces a combined image containing the drawn image,followed by projection of the combined image via the projection section35, image data on the projected combined image is temporarily stored asthe projection image data 324.

The frame memory 341 is connected to the image processing section 34.

The image processing section 34 acquires image data from an image sourceselected under the control of the control section 31 and performs avariety of types of image processing on the acquired image data. Forexample, the image processing section 34 carries out a resolutionconversion process of converting the resolution of the image data inaccordance with the display resolution of the light modulator 352. Theimage processing section 34 further carries out a geometric correctionprocess of correcting the shape of the image, a color tone correctionprocess of correcting the color tone of the image data, and otherprocesses. The image processing section 34 can further perform imageprocessing that rotates the orientation of an image projected by theprojection section 36 by 180 degrees under the control of the controlsection 31. The image processing section 34 produces an image signal fordisplaying the processed image data and outputs the image signal to thelight modulator driving section 336.

To perform image processing, the image processing section 34 (imageproducing section) develops an image based on image data acquired froman image source in the frame memory 341 and performs a variety of typesof processing on the image developed in the frame memory 341. Forexample, the image processing section 34 superimposes an image drawn byoperation of the pointing element 203 on the image in the frame memory341 so that the two images are combined with each other to produce acombined image (superimposed image) under the control of the drawingcontrol section 312. To display an image for GUI operation, the imageprocessing section 34 superimposes an image based on the GUI data 322 onthe image in the frame memory 341 so that the two images are combinedwith each other to produce a combined image. The image processingsection 34 may output image data on the combined image combined in theframe memory 341 to the storage section 32 and cause the storage section32 to store the image data as the projection image data 324. In a casewhere the projection control section 311 instructs the image processingsection 34 to capture the projection image, the image processing section34 may output the image data in the frame memory 341 to the storagesection 32 and cause the storage section 32 to store the image data asthe projection image data 324.

In the present embodiment, the single image processing section 34processes the projection images P3 and P4. Further, the images processedby the image processing section 34 are formed by the single lightmodulator 352. In this case, the image processing section 34 mayalternately develop the image projected by the projection section 35 andthe image projected by the projection section 36 in the frame memory341. Instead, the image processing section 34 may be so configured thatthe frame memory 341 has an area where the image projected by theprojection section 35 is developed and an area where the image projectedby the projection section 36 is developed.

The image processing section 34 outputs an image signal to the lightmodulator driving section 326 to cause the light modulator 352 toalternately form two images. The two images are the projection image P3projected by the projection section 35 and the projection image P4projected by the projection section 36. Specifically, the imageprocessing section 34 updates the image formed in the light modulator352 in a predetermined cycle, and the update cycle is determined asappropriate by the rotating speed of the motor 354, the ratio of thesize of a light transmissive section 356 to the size of a flat surface355 a, and other factors.

The light source driving section 335 supplies the light source 351 withdrive current and pulses to cause the light source 351 to emit light.The light source driving section 335 may be capable of adjusting theluminance of the light emitted from the light source 351. The lightmodulator driving section 336 drives the light modulator 352 on thebasis of an image signal input from the image processing section 34 todraw an image in the light modulator 352 on a frame basis under thecontrol of the control section 31.

The voice processing section 381 outputs voice via the loudspeaker 382on the basis of input digital voice data or an input analog voice signalunder the control of the control section 31.

In the projectors 11 and 13 described above, the projection sections 25,26, 35, and 36 have been described as examples of the configuration inwhich different projection images are projected in two differentdirections. The configurations of the projection sections 25, 26, 35,and 36 are presented only by way of example. For example, the projector13 may have the same configurations as those of the projection sections25 and 26, or the projector 11 may have the same configurations as thoseof the projection sections 35 and 36. Instead, an optical part having nomovable portion may be used to divide or distribute the modulated imagelight from the light modulator in a plurality of directions, and imagesmay be projected in the plurality of directions. In addition, theconfiguration in which each of the projectors 11 and 13 projectsdifferent projection images in a plurality of directions can bearbitrarily changed.

FIG. 6 is a block diagram of the projector 15.

The projector 15 includes the control section 51, the storage section52, the wireless communication section 53, the image processing section54, and the projection section 55, as described above. The projector 15further includes a light source driving section 535, a light modulatordriving section 536, an image interface section 543, an interfacesection 545, an input processing section 547, and a voice processingsection 581. The sections described above are connected to each othervia a bus 580. Further, a frame memory 541 is connected to the imageprocessing section 54, and an operation panel 585 and a remote controllight receiving section 587 are connected to the input processingsection 547, as will be described later. A loudspeaker 582 is connectedto the voice processing section 581.

The image interface section 543 (second acquisition section) is aninterface that connects the image source apparatus described above tothe projector 15 and includes a connector, an interface circuit, andother components. The image interface section 543 may include aconnector to which a card-shaped recording medium, such as an SD memorycard, a USB memory device, or any other portable storage medium can beconnected, and an interface circuit.

The image interface section 543 is not limited to the configuration inwhich it is wired to the image source apparatus. For example, the imageinterface section 543 may be configured to perform wireless datacommunication that complies with a wireless LAN (including Wi-Fi),Miracast (registered trademark), Bluetooth (registered trademark), orany other standard with the image source apparatus.

Digital image data in a data format that can be processed by theprojector 15 is input to the image interface section 543. The digitalimage data may be still image data or motion image data. In thefollowing description, data input from the image source apparatus to theimage interface section 543 is called input image data OS3.

The image interface section 543 is not limited to an interface to whichdigital image data can be input and may, for example, have aconfiguration to which an analog image (video) signal can be input. Inthis case, the input image data OS3 may be an analog signal. In thiscase, the image interface section 543 may have the function ofconverting an analog signal into digital data.

The interface section 545 is connected to an external apparatus, such asa PC, and transmits and receives a variety of data, such as the controldata, to and from the external apparatus. For example, the interfacesection 545 performs data communication that complies with Ethernet,IEEE 1394, USB, or any other standard.

The projection section 55 includes a light source 551, a light modulator552, which modulates light emitted from the light source 551 to produceimage light, and a projection system 553, which projects the modulatedimage light from the light modulator 552 on the flat surface PL3.

The light source 551 is formed of a halogen lamp, a xenon lamp, anultrahigh-pressure mercury lamp, or any other lamp or an LED, a laserlight source, or any other solid-state light source. The light source551 is turned on by using electric power supplied from the light sourcedriving section 535 and emits light toward the light modulator 552.

The light modulator 552 modulates the light emitted from the lightsource 551 to produce image light and irradiates the projection system553 with the image light.

The light modulator 552 includes, for example, a transmissive liquidcrystal light valve, a reflective liquid crystal light valve, a digitalmirror device, or any other light modulating element. The lightmodulator driving section 536 is connected to the light modulatingelement of the light modulator 552. The light modulator driving section536 drives the light modulator 552 on the basis of an image signaloutputted from the image processing section 54. The light modulatordriving section 536 drives the light modulating element of the lightmodulator 552 to set the grayscale of each pixel so that an image isdrawn on a frame (screen) basis in the light modulating element.

The projection system 553 includes a lens and a mirror that focus thelight modulated by the light modulator 552 on a screen. The projectionsystem 553 may further include a zoom lens, a focus lens, and a varietyof other lenses or lens groups.

The input processing section 547 accepts the user's operation.

The input processing section 547 detects operation performed on theoperation panel 585. The operation panel 585 is disposed, for example,on the enclosure of the projector 15 and includes a variety of switches.The input processing section 547 detects operation performed on any ofthe switches on the operation panel 585 and outputs control datarepresenting the operated switch to the control section 51.

The remote control light receiving section 587, which is connected tothe input processing section 547, receives an infrared signaltransmitted from a remote control 50 and decodes the received signal.The remote control 50 includes a variety of switches and transmits aninfrared signal representing an operated switch. The remote controllight receiving section 587 decodes the received signal and outputs dataon the decoded signal to the input processing section 547. The inputprocessing section 547 outputs the data input from the remote controllight receiving section 587 to the control section 51.

The control section 51 includes, for example, a CPU, a flash ROM, and aRAM that are not shown. The control section 51, in which the CPUexecutes a program stored in the flash ROM or the storage section 52,controls each portion of the projector 15. The control section 51includes a projection control section 511, an operation acquiringsection 513, and a communication control section 514 as functionalblocks that control the portions of the projector 15. The functionalblocks are achieved by cooperation between software and hardware whenthe CPU of the control section 51 executes the program.

The projection control section 511 controls the image processing section54, the light source driving section 535, the light modulator drivingsection 536, and other portions to control the projection of theprojection image P5 performed by the projector 15. The projectioncontrol section 511 controls the timing when a process carried out bythe image processing section 54 is carried out, a condition under whichthe process is carried out, and other factors associated with theprocess. The projection control section 511 further controls the lightsource driving section 535 to, for example, adjust the luminance of thelight emitted from the light source 551.

The projection control section 511 selects an image source of theprojection image P5 on the basis of the user's operation acquired by theoperation acquiring section 513. The projection control section 511controls the image processing section 54 to cause it to acquire imagedata from the selected image source.

The projection control section 511 further performs projection imageswitching control in which the projection image P5 is switched to theprojection image P1 or P2 projected by the projector 11, the projectionimage P3 or P4 projected by the projector 13, or any other image. Inthis case, the projection control section 511 changes the image sourceof the projection image P5 to the image data transmitted from theprojector 11 or 13 and temporarily stored in the storage section 52.

The projection control section 511 further causes the projector 11 or 13to project the projection image P5. In this case, the projection controlsection 511 transmits the image data on the projection image P5 inaccordance with the control data transmitted from the projector 11 or 13under the control of the communication control section 514.

The projection control section 511 further controls the imaging section57 to cause it to perform imaging to acquire captured image data. Theprojection control section 511 may perform projection by using theacquired captured image data as the image source. The projection controlsection 511 may instead temporarily store the captured image data fromthe imaging section 57 in a DRAM 525 and, for example, transmit thecaptured image data to another projector. The imaging section 57 is animaging section so disposed as to image, for example, the flat surfacePL3. More specifically, the imaging section 57 may perform imaging overa viewing angle containing the projection image P5. In this case, theimaging section 57 can image the projection image P5 projected by theprojector 15. Further, for example, in a case where a diagrammaticpicture of an actual object is placed on the flat surface PL3 and theprojector 15 projects the projection image P5 in such a way that theprojection image P5 is superimposed on the diagrammatic picture, animage captured with the imaging section 57 contains the projection imageP5 superimposed on the diagrammatic picture of the actual object. Thatis, image data on the state in which the projection image P5 issuperimposed on the diagrammatic picture of the actual object can beproduced.

The operation acquiring section 513 detects operation performed on theprojector 15. The operation acquiring section 513 detects operationperformed via the remote control 50 and the operation panel 585, whichfunction as input devices, on the basis of data input from the inputprocessing section 547.

The storage section 52 is a storage device that stores data processed bythe control section 51 and the program executed by the CPU of thecontrol section 51. The storage section 52 can be configured to includea variety of volatile storage devices and/or nonvolatile storagedevices. In the present embodiment, the storage section 52 includes aflash ROM 520 and the DRAM 525. The flash ROM 520 is configured in thesame manner as the flash ROM 220, and the DRAM 525 is configured in thesame manner as the DRAM 225. The flash ROM 520 stores setting data 521,and the DRAM 525 stores content data 523 and projection image data 524.When the projector 15 is powered off, the content data 523 and theprojection image data 524 may be saved in the flash ROM 520.

The setting data 521 contains a variety of setting values (parameters)that specify actions of the projector 15. The setting data 521 contains,for example, setting values that allow the projector 15 to performwireless data communication over the communication network 10.Specifically, the setting data 511 contains identification information,such as the network addresses and the IDs of the projectors 11, 13, and15 and the wireless communication apparatus 9, and authenticationinformation, such as pass phrases thereof. The setting data 521 mayfurther contain data that specifies the type or content of imageprocessing performed by the image processing section 54 and parametersused in the image processing.

The content data 523 contains still image data or motion image data thatcan be selected as an image source. The content data 523 may containvoice data.

The projection image data 524 contains image data received from theprojector 11 or 13. That is, in a case where the projector 15 receivesimage data on a projection image from the projector 11 or 13, thereceived image data is stored as the projection image data 524.

The frame memory 541 is connected to the image processing section 54.

The image processing section 54 acquires image data from an image sourceselected under the control of the control section 51 and performs avariety of types of image processing on the acquired image data. Forexample, the image processing section 54 carries out a resolutionconversion process of converting the resolution of the image data inaccordance with the display resolution of the light modulator 552. Theimage processing section 54 further carries out a geometric correctionprocess of correcting the shape of the image, a color tone correctionprocess of correcting the color tone of the image data, and otherprocesses. The image processing section 54 produces an image signal fordisplaying the processed image data and outputs the image signal to thelight modulator driving section 536.

To perform image processing, the image processing section 54 develops animage based on image data acquired from an image source in the framememory 541 and performs a variety of types of processing on the imagedeveloped in the frame memory 541.

The image processing section 54 outputs the image signal to the lightmodulator driving section 536 to cause the light modulator 552 to forman image.

The light source driving section 535 supplies the light source 551 withdrive current and pulses to cause the light source 551 to emit light.The light source driving section 535 may be capable of adjusting theluminance of the light emitted from the light source 551. The lightmodulator driving section 536 drives the light modulator 552 on thebasis of an image signal input from the image processing section 54 todraw an image in the light modulator 552 on a frame basis under thecontrol of the control section 51.

The voice processing section 581 outputs voice via the loudspeaker 582on the basis of input digital voice data or an input analog voice signalunder the control of the control section 51.

FIG. 7 shows an example of the GUI operation in the projection system 1.

The user who operates the projection system 1 can perform GUI operationusing the pointing element 201 on the projector 11. The operation of theprojector 11 will be described below, and the user can similarly performGUI operation using the pointing element 203 on the projector 13.

In the projection area where the projector 11 projects the projectionimage P1, a detection area 200, where a pointed position pointed withthe pointing element 201 can be detected, is set. In the example shownin FIG. 7, the detection area 200 is so set as to be slightly smallerthan the projection image P1, but the detection area 200 may instead belarger than the projection image P1.

When the user operates the operation panel 285 or the remote control 20to instruct start of the GUI operation or display of the menu bar, thecontrol section 21 displays the menu bar 206 on the basis of the GUIdata 222 stored in the storage section 22. The menu bar 206 (image foroperation) contains a variety of icons for setting attributes of afigure drawn by operation of the pointing element 201. The attributes ofa figure are the shape of the figure, the color, thickness, and otherfactors of lines that form the drawn figure. The user can specify anicon in the menu bar 206 by aligning the position of the front end 202of the pointing element 201 with the icon for operation of specifyingthe attributes.

After operation that specifies the attributes of the figure, the useroperates the pointing element 201 to produce a drawn image 205 along thetrajectory of the front end 202, as shown, for example, in FIG. 7.

A display switching icon 207 is placed in the menu bar 206. The displayswitching icon 207 is an icon for instructing projection imageswitching, for example, for causing the projector 13 or 15 to displaythe projection image P1 or P2 projected by the projector 11. When theuser operates the display switching icon 207 by using the pointingelement 201, the control section 21 detects that image switching hasbeen instructed and carries out the image switching process. In thiscase, the operation of the display switching icon 207 is followed, forexample, by operation of selecting a switchover source image and aswitchover destination image from the projection images P1 to P5.

FIGS. 8, 9, and 10 are flowcharts showing actions of the projectionsystem 1. FIGS. 8 and 9, in particular, show actions performed by theprojector 11 or 13 in accordance with a projection image switchinginstruction. Therefore, the actions in FIGS. 8 and 9 may be performed bythe projector 11 or may be performed by the projector 13 and will bedescribed as actions performed by the projector 11. FIG. 10 showsactions performed by any of the projectors 11, 13, and 15 in accordancewith control data transmitted from any of the other projectors. In thefollowing description, the actions will be described as those performedby the projector 15.

In short, the following description will be made of the action ofswitching the projection image P5 projected by the projector 15 to theprojection image P1 or P2 projected by the projector 11 as an example ofthe actions of the projection system 1. In another expression, theprojector 15 is caused to project the projection image P1 or P2. In thiscase, the projector 11 may switch the image projected by the projector15 to the other one of the projection image P1 or P2.

The projector 11, after it is powered on, performs initial setting andother operation and then starts performing the actions in FIG. 8.

The control section 21 of the projector 11 selects an image source on aprojection direction basis in accordance with the user's operationaccepted by the input processing section 247 or the setting data 221 setin advance (step S11). Specifically, the control section 21 selects theimage source of the projection image P1 and the image source of theprojection image P2. The control section 21 causes the image processingsection 24 to acquire image data from the selected image sources andcauses the projection sections 25 and 26 to project the projectionimages P1 and P2, respectively (step S12). It is noted that no imagesource may be selected for one of or both the projection section 25(projection image P1) nor the projection section 26 (projection imageP2). Any of the projection sections 25 and 26 for which no image sourceis selected projects no image.

The control section 21 evaluates whether or not operation accepted bythe input processing section 247 has instructed display of the menu bar206 (step S13). In a case where the display of the menu bar 206 has beeninstructed (Yes in step S13), the control section 21 causes theprojection section 25 to display the menu bar 206 on the basis of theGUI data 222 (step S14). At this point, the control section 21 startspointed position detection performed by the position detecting section27 and therefore transitions to the state that allows the user toperform operation by using the pointing element 201 (step S15).

The control section 21 waits for operation performed on the menu bar 206and evaluates whether or not drawing has been instructed (step S16). Ina case where drawing has been instructed (Yes in step S16), the controlsection 21 performs drawing on the basis of pointed positions detectedby the position detecting section 27 (step S17), causes the imageprocessing section 24 to produce combined image data, and causes thestorage section 22 to store the combined image data (step S18). Thecontrol section 21 causes the image processing section 24 and theprojection section 25 to project the combined image (step S19).

The control section 21 evaluates whether or not drawing termination hasbeen instructed (step S20), and in a case where the drawing is notterminated (No in step S20), the control section 21 returns to step S17.In a case where drawing termination has been instructed (Yes in stepS20), the control section 21 evaluates whether or not the projectionbeing performed by the projector 11 is terminated (step S21). In stepS21, the control section 21 performs the evaluation based, for example,on whether or not operation accepted by the input processing section 247has instructed projection termination or power-off of the projector 11.In a case where the projection is terminated (Yes in step S21), thecontrol section terminates the present process. In a case where theprojection is not terminated (No in step S21), the control section 21returns to step S13.

In a case where display of the menu bar 206 has not been instructed instep S13 (No in step S13), the control section 21 proceeds to step S21.

In a case where drawing has not been instructed in step S16 (No in stepS16), the control section 21 evaluates whether or not image switchinghas been instructed (step S22). In a case where no image switching hasbeen instructed (No in step S22), the control section 21 proceeds tostep S21. In a case where image switching has been instructed (Yes instep S22), the control section 21 carries out the process of switchingprojection images in the projection system 1 (step S23).

FIG. 9 is a flowchart showing the switching process in detail.

In the switching process, a switchover source projection image and aswitchover destination projection image are specified by operationaccepted by the input processing section 247 or GUI operation using thepointing element 201 (step S31). The switching process is the process ofswapping some of the projection images P1 to P5 projected by theprojection system 1. In more detail, the switching process is theprocess of causing any of the projection images P1 to P4 projected bythe projectors 11 and 13 to be projected as any of the other projectionimages out of projection images P1 to P5 projected by the projectors 11,13, and 15. In another expression, the switching process is the processof replacing any of the projection images P1 to P5 with any of theprojection images P1 to P4.

In step S31, target projection images in the switching process arespecified. The target projection images in the switching process includea switchover source projection image and a switchover destinationprojection image. In the description, the projector 15 is caused toproject the projection image P1 projected by the projector 11, asdescribed above. That is, the projection image P5 is switched to theprojection image P1. In the example, the switchover source is theprojection image P1, and the switchover destination is the projectionimage P5. The switchover source projection image and the switchoverdestination projection image may be projection images projected by thesame projector.

In the switching process, the control section 21 produces control datathat instructs a projector that projects a switchover destinationprojection image to perform the projection image switching (step S32).The control section 21 causes the wireless communication section 23 totransmit the produced control data to the projector that projects theswitchover destination projection image (step S33).

The control section 21 evaluates whether or not the switchover sourceprojection image is a combined image (step S34). In a case where theswitchover source projection image is a combined image (Yes in stepS34), the control section 21 sets the combined image data stored in thestorage section 22 as the image source (step S35).

The image processing section 24, when it produces a combined image,stores the image data on the combined image in the storage section 22,as described in step S18 (FIG. 8). In a case where the switchover sourceprojection image is a combined image, the control section 21 sets thecombined image data stored in the storage section 22 as the switchoversource image source (step S35). The control section 21 startstransmitting the image data set as the image source (step S36). Afterstep S36, the wireless communication section 23 transmits the image dataspecified by the control section 21 to the projector 15 that projectsthe switchover destination projection image.

In a case where the switchover source projection image is not a combinedimage (No in step S34), the control section 21 proceeds to step S36 andstarts transmitting image data set as the image source of the switchoversource projection image (step S36).

As described above, in the case where projection image switching hasbeen instructed, for example, by GUI operation using the pointingelement 201, the projector 11 can cause another projector, the projector13 or 15, to project the image being projected as the projection imageP1 or P2. The actions shown in FIGS. 8, 9, and 10 are not necessarilyperformed by the projector 11 and may instead be performed, for example,by the projector 13. That is, the switchover source projection image mayinstead be the projection image P3 or P4.

The projector that projects the switchover destination projection imagereceives the control data transmitted by the projector 11 in step S33(FIG. 9) and performs the actions shown in FIG. 10. The actions shown inFIG. 10 will be described as those of the projector 15. That is, theswitchover destination projection image is the projection image P5.

The control section 51 of the projector 15 waits for reception of thecontrol data transmitted by the switchover source projector (step S51).The control data is the control data transmitted by the projector 11 instep S33 in FIG. 9. In a case where no control data has been received(No in step S51), the control section 51 terminates the present process.

In a case where the control data that instructs projection imageswitching has been received (Yes in step S51), the control section 51starts receiving image data to be projected (step S52). The image datais the image data transmitted, for example, by the projector 11 in stepS36 in FIG. 9. At this point, the control section 51 stores the receivedimage data as the projection image data 524 in the storage section 52.

The control section 51 sets the received image data as the image sourceof the projection image P5 (step S53). The control section 51 stores theimage data received by the wireless communication section 53 after stepS52 in the storage section 52 as the projection image data 524 andtherefore sets the projection image data 524 as the image source.

Assume, as an example, a case where the user plays the role of a teacherand uses the projection system 1 for education (class, lecture) or otherpresentation (such as seminar) purposes. In this case, a lecture or apresentation can be performed by causing the projector 11 to project theprojection image P1 from image sources, such as document data, stillimage data on figures for presentation, and motion image data. In thisstate, it is conceivable that the user desires to show, while showingthe projection image P1 to the audience (lecture participants, pupils,students), another document or image. In this case, the user can operatethe projector 11 to perform the projection image switching. The contentprojected in the form of the projection image P1 can therefore beprojected as the projection image P2 on the flat surface PL4 or by theprojector 13 or 15. Therefore, the image shown to the audience can beshown continuously, and another image can be shown in the form of theprojection image P1.

The projector 11 can draw a figure in correspondence with operation ofthe pointing element 201 by using the function of the image processingsection 24, as illustrated in FIG. 7. The projector 11 can furtherproject a drawn image in such a way that the drawn image is superimposedon the image source of the projection image P1. Specifically, in a statein which a document is projected as the projection image P1, lines andletters drawn in accordance with operation of the pointing element 201can be superimposed on the document to form a combined image, and thecombined image can be projected as the projection image P1. Further, theprojector 11 may combine the document data, which is the image source,with, for example, another still image data in such a way that the stillimage data is superimposed on the document data by using the function ofthe image processing section 24 and may project the resultant combinedimage as the projection image P1.

In this case, the projection system 1 can project the combined image,which is projected as the projection image P1, as the projection imageP2 or any of the projection images P3 to P5.

Further, the projection image switching process can be carried out againin such a way that the image projected as the projection image P2 or anyof the projection images P3 to P5 is restored to the projection imageP1. For example, during a class or a lecture, in a state in which animage of a sentence, a figure, a material, or any other piece ofinformation is projected as the projection image P1, in a case where itis desired that another image is projected in place of the projectionimage P1, the projection image P1 can be transferred to the ceiling(flat surface PL4) or another projection surface of the room (flatsurface PL2 or PL3).

To use the approach described above with a typical projector of relatedart, for example, the image being projected is captured, the capturedimage data is stored, and the projection image is temporarily deleted.Thereafter, the captured image data is read and reproduced as required.As compared with the approach described above, according to the functionof the projection system 1, the teacher and audience can advantageouslyview a single image or a plurality of images moved to other projectionsurfaces anytime as required. That is, the user who is the teacherprimarily uses the projection image P1 and can freely swap the imageprojected as the projection image P1 and an image projected as any ofthe other projection images, the projection images P2 to P5. The lectureand presentation can therefore be given by simultaneously using theprojection images P1 to P5.

When the projection image switching is performed, the projectors 11 and13 may change the orientation of the projection images P2 and P4projected on the flat surface PL4. The orientation changing action canbe achieved by the process of reversing an image formed by the imageprocessing section 24 in the frame memory 241 upside down or rotatingthe image by 180°. The same holds true for an image formed by the imageprocessing section 34 in the frame memory 341. In this case, thedirections of the projection images P2 and P4 can be switched todirections that allow users who face the flat surfaces PL1 and PL3 toreadily view the projection images P2 and P4 and directions that allowthe audience present in positions away from the flat surfaces PL1 andPL3 to readily view the projection images P2 and P4.

In the configuration described above, the projectors 11 and 13 canperform the actions shown in FIGS. 8 and 9, and the projectors 11, 13,and 15 can perform the actions shown in FIG. 10. In the projectionsystem 1, the projectors that can perform the actions shown in FIGS. 8and 9 may be limited to a specific projector. For example, the projector11 may be configured to be capable of performing the actions describedabove, and the projector 13 may be configured not to perform thefunction of transmitting the control data that instructs projectionimage switching. Further, the projector 13 may be configured not toperform drawing or GUI operation using the pointing element 203. In thiscase, the projector 13 may be configured to be incapable of performingoperation using the pointing element 203, or the projector 13 may be soconfigured that a specific setting on the projector 13 restricts theaction and operation described above.

The above configuration has been described with reference to the casewhere the projection image P1 from the projector 11 is projected as theprojection image P5 from the projector 15. Instead, the two projectionimages from the projectors 11 and 15 may be interchanged. The same holdstrue for interchange of two projection images between the projectors 13and 15 and between the projectors 11 and 13. In this case, for example,in a case where the projection image P1 is the switchover source and theprojection image P3 is the switchover destination, the switching may beso performed that not only does the projector 13 project the projectionimage P1 but the projector 11 projects the projection image P3.

Further, the present embodiment shows the configuration byway of examplein which the projection system 1 includes the projectors 11 and 13 asprojectors capable of projecting projection images in two directions.That is, the present embodiment describes the case using the projector11, which includes the two light sources 251 and 261 and the two lightmodulators 252 and 262, and the projector 13, which includes the singlelight source 351 and the single light modulator 352, but the inventionis not limited thereto. For example, the projection system 1 may beconfigured to include one of the projector 11 and the projector 13. Theprojection system 1 may instead be configured to include one or moreprojectors 11 or one or more projectors 13 or may still instead beconfigured to include any of the projectors 11 and 13 described aboveand the projector 15.

As described above, the projection system 1 according to the embodimentincludes a first projector that projects an image on the basis of imagedata in a first projection direction and a second projector thatprojects an image on the basis of image data in a second projectiondirection. The projection system 1 further includes a storage sectionthat stores the image data representing the image projected by the firstprojector and can switch the image projected by the second projector tothe image based on the image data stored in the storage section.

The projectors 11 and 13 can be used as the first projector.

In a first aspect of the invention, the projector 11 corresponds to thefirst projector, and the projector 13 and/or the projector 15corresponds to the second projector. The storage sections 22, 32, 52correspond to the storage section.

In a second aspect, the projector 13 corresponds to the first projector,and the projector 11 and/or the projector 15 corresponds to the secondprojector. In the first and second aspects, the storage sections 22, 32,52 correspond to the storage section.

According to the projection system 1, to which the invention is applied,and the method for controlling the projection system 1, the secondprojector can project the image projected by the first projector. In thefirst aspect, the projection image P1 or P2 projected by the projector11 can be projected as the projection image P3 or P4 from the projector13 or the projection image P5 from the projector 15. In the secondaspect, the projection image P3 or P4 projected by the projector 13 canbe projected as the projection image P1 or P2 from the projector 11 orthe projection image P5 from the projector 15.

As described above, an image projected by any of the projectors 11 and13 can be changed to another image, and the image before the change canbe projected by any of the projectors 11, 13, and 15. The number ofimages projected by the projectors 11 and 13 can therefore besubstantially increased. The projectors 11, 13, and 15 can thereforeproject a large amount of information.

The projection system 1 includes an acceptance section that accepts aninstruction input and switches the image projected by the secondprojector to the image based on the image data stored in the storagesection in accordance with the instruction input accepted by theacceptance section. In the first aspect, the input processing section247 corresponds to the acceptance section. In this case, one or more ofthe projection images P3 and P4 projected by the projector 13 and theprojection image P5 projected by the projector 15 can be switched toother projection images in accordance with the instruction inputaccepted by the input processing section 247. Image data on a switchoversource image can be the projection image data 224 stored in the storagesection 22, the projection image data 324 stored in the storage section32, or the projection image data 524 stored in the storage section 52.In the second aspect, the input processing section 347 corresponds tothe acceptance section. In this case, one or more of the projectionimages P1 and P2 projected by the projector 11 and the projection imageP5 projected by the projector 15 can be switched to other projectionimages in accordance with the instruction input accepted by the inputprocessing section 347. Image data on a switchover source image can bethe projection image data 224 stored in the storage section 22, theprojection image data 324 stored in the storage section 32, or theprojection image data 524 stored in the storage section 52.

As described above, an image projected by any of the projectors 11, 13,and 15 can be switched to another in accordance with an instructioninput in the projection system 1. An image projected by any of theprojectors 11, 13, and 15 can then be projected by any of the remainingprojectors out of the projectors 11, 13, and 15. In this case, theprojectors 11, 13, and 15 do not need to be set in advance at the statein which no image is projected, whereby convenience provided by theprojection system 1 can be improved.

The projection system 1 according to the embodiment of the inventionincludes the first projector and the second projector. The firstprojector includes a first acquisition section that acquires image dataand a first projection section that projects an image on the basis ofthe image data acquired by the first acquisition section. The firstprojector further includes a first storage section that stores the imagedata representing the image projected by the first projection sectionand a first communication section that transmits the image data storedin the first storage section to the second projector. The secondprojector includes a second acquisition section that acquires image dataand a second projection section that projects an image on the basis ofthe image data acquired by the second acquisition section. The secondprojector further includes a second communication section that receivesthe image data from the first projector and a second storage sectionthat stores the image data received by the second communication section.The second projector can perform the action in which the secondprojection section projects the image on the basis of the image dataacquired by the second acquisition section and the action in which thesecond projection section projects the image on the basis of the imagedata stored in the second storage section with the two actions switchedfrom one to the other.

In the first aspect, the projector 11 includes the image interfacesection 243, which acquires image data, and the projection sections 25and 26, which project images on the basis of the image data acquired bythe image interface section 243. In this case, the projection section 25or 26 corresponds to the first projection section. The projector 11further includes the storage section 22, which stores the projectionimage data 224, which is image data on images projected by theprojection sections 25 and 26, and the wireless communication section23, which transmits the projection image data 224 to the projector 13 or15. The projector 13 includes the image interface section 343, whichacquires image data, and the projection sections 35 and 36, whichproject images on the basis of the image data acquired by the imageinterface section 343. In this case, the projection section 35 or 36corresponds to the second projection section. The projector 13 furtherincludes the wireless communication section 33, which receives imagedata from the projector 11, and the storage section 32, which stores theimage data received by the wireless communication section 33 as theprojection image data 324. The projector 13 can perform the followingactions performed via the projection sections 35 and 36: the action ofprojecting the image on the basis of the image data acquired by theimage interface section 343; and the action of projecting the image onthe basis of the projection image data 324, with the two actionsswitched from one to the other. In the case where the second projectoris the projector 15, the projector 15 includes the image interfacesection 543, which acquires image data, and the projection section 55,which projects an image on the basis of the image data acquired by theimage interface section 543. The projector 15 further includes thewireless communication section 53, which receives image data from theprojector 11, and the storage section 52, which stores the image datareceived by the wireless communication section 53 as the projectionimage data 524. The projector 15 can perform the following actionsperformed via the projection section 55: the action of projecting theimage on the basis of the image data acquired by the image interfacesection 543; and the action of projecting the image on the basis of theprojection image data 524, with the two actions switched from one to theother.

An image from the projector 11 or 13 can thus be projected by any of theremaining projectors out of the projectors 11, 13, and 15. Therefore, ina case where an image projected by the projector 11 or 13 is changed toanother image, the image before the change can be projected by the otherone of the projectors 11, 13, and 15 whereby the number of imagesprojected by the projectors 11 and 13 can be substantially increased.The projectors 11, 13, and 15 can therefore project a larger amount ofinformation.

In the projection system 1, the first projector includes a switchingcontrol section that produces control data that instructs the secondprojector to perform image switching and causes the first communicationsection to transmit the control data to the second projector. The secondprojector, when it receives the control data via the secondcommunication section, switches the action in which the secondprojection section projects the image on the basis of the image dataacquired by the second acquiring section to the action in which thesecond projection section projects the image on the basis of the imagedata stored in the second storage section and vice versa.

In the first aspect, the control section 21 of the projector 11corresponds to the switching control section. The projector 11 includesthe control section 21, which produces control data that instructs theprojector 13 or 15 to perform image switching and causes the wirelesscommunication section 23 to transmit the control data to the projector13 or 15. The projector 13, when it receives the control data via thewireless communication section 23, can switch the action thereof betweenthe actions described above. That is, the projector 13 switches thefollowing actions performed via the projection sections 35 and 36 fromone to the other: the action of projecting the image on the basis of theimage data acquired by the image interface section 343; and the actionof projecting the image on the basis of the projection image data 324stored in the storage section 32. Further, the projector 15, when itreceives the control data via the wireless communication section 53, canswitch the action thereof between the actions described above. That is,the projector 15 switches the following actions performed via theprojection section 55 from one to the other: the action of projectingthe image on the basis of the image data acquired by the image interfacesection 543; and the action of projecting the image on the basis of theprojection image data 524 stored in the storage section 52.

In the second aspect, the projector 13 includes the control section 31,which produces control data that instructs the projector 11 or 15 toperform image switching and causes the wireless communication section 33to transmit the control data to the projector 11 or 15. The projector11, when it receives the control data via the wireless communicationsection 33, can switch the action thereof between the actions describedabove. That is, the projector 11 switches the following actionsperformed via the projection sections 25 and 26 from one to the other:the action of projecting the image on the basis of the image dataacquired by the image interface section 243; and the action ofprojecting the image on the basis of the projection image data 224stored in the storage section 22. Further, the projector 15, when itreceives the control data via the wireless communication section 53, canswitch the action thereof between the actions described above. That is,the projector 15 switches the following actions performed via theprojection section 55 from one to the other: the action of projectingthe image on the basis of the image data acquired by the image interfacesection 543; and the action of projecting the image on the basis of theprojection image data 524 stored in the storage section 52.

Transmission of the control data from the projector 11 or 13 thereforeallows an image projected by any of the remaining projectors out of theprojectors 11, 13, and 15 to be switched to the image projected by theprojector 11 or 13. The operation required to perform the projectionimage switching in the projection system 1 can therefore be simplified,whereby the convenience provided by the projection system 1 can beimproved.

In the projection system 1, a first control section provided in thefirst projector allows projection of an image for operation on the basisof data representing the image for operation, the first projectorincludes an acceptance section that accepts operation performed on theimage for operation projected by the first projection section, and theswitching control section produces the control data on the basis of theoperation accepted by the acceptance section and causes the firstcommunication section to transmit the control data to the secondprojector.

In the first aspect, the control section 21 provided in the projector 11corresponds to the first control section. The projector 11 can projectthe image for operation on the basis of the data representing the imagefor operation. For example, the GUI data 222 corresponds to the datarepresenting the image for operation, and the menu bar 206 correspondsto the image for operation. The projector 11 includes the positiondetecting section 27, which accepts operation performed on the image foroperation projected by the projection section 25 or 26. The controlsection 21 produces the control data on the basis of the operationaccepted by the position detection section 27 and causes the wirelesscommunication section 23 to transmit the control data to the projector13 or 15.

In the second aspect, the control section 31 provided in the projector13 corresponds to the first control section. The projector 13 canproject the image for operation on the basis of the data representingthe image for operation. For example, the GUI data 322 corresponds tothe data representing the image for operation. The projector 13 includesthe position detecting section 37, which accepts operation performed onthe image for operation projected by the projection section 35 or 36.The control section 31 produces the control data on the basis of theoperation accepted by the position detection section 37 and causes thewireless communication section 33 to transmit the control data to theprojector 11 or 15.

Operation using the image for operation can thus readily instructprojection image switching in the projection system 1.

In the projection system 1, the first projector includes a positiondetecting section that detects a position input and an image producingsection that produces an image on the basis of a position detected bythe position detecting section. The first projection section projects animage based on combined image data formed of image data representing theimage produced by the image producing section combined with the imagedata acquired by the first acquisition section. The first storagesection stores the combined image data, and the first communicationsection transmits the combined image data stored in the storage sectionto the second projector.

In the first aspect, the projector 11 includes the position detectingsection 27, which detects a position input, and the image processingsection 24, which produces an image on the basis of a position detectedby the position detection section 27. The projection section 25 or 26projects an image based on combined image data formed of image datarepresenting the image produced by the image processing section 24combined with the image data acquired by the image interface section243. The storage section 22 stores the combined image data as theprojection image data 224, and the wireless communication section 23transmits the combined image data stored in the storage section 22 tothe projector 13 or 15.

In the second aspect, the projector 13 includes the position detectingsection 37, which detects a position input, and the image processingsection 34, which produces an image on the basis of a position detectedby the position detection section 37. The projection section 35 or 36projects an image based on combined image data formed of image datarepresenting the image produced by the image processing section 34combined with the image data acquired by the image interface section343. The storage section 32 stores the combined image data as theprojection image data 324, and the wireless communication section 33transmits the combined image data stored in the storage section 32 tothe projector 11 or 15.

Therefore, in a case where the projector 11 or 13 produces an imagebased on a position input and projects the image, the other projectorcan display a projection image containing the produced image.

In the projection system 1, the first projector includes a thirdprojection section that projects an image in a direction different fromthe direction in which the first projection section projects an image.The first projector can cause the third projection section to project animage based on the image data acquired by the first acquisition sectionand an image based on the image data stored in the first storage sectionwith the two images switched from one to the other.

In the first aspect, the projector 11 includes the projection section26, which projects an image in a direction different from the directionin which the projection section 25 projects an image. The projector 11cause the projection section 26 to project an image based on the imagedata acquired by the image interface section 243 and an image based onthe image data stored in the storage section 22 with the two imageswitched from one to the other. In this aspect, the first projectionsection may be the projection section 25 and the third projectionsection may be the projection section 26, or vice versa.

In the second aspect, the projector 13 includes the projection section36, which projects an image in a direction different from the directionin which the projection section 35 projects an image. The projector 13can cause the projection section 36 to project an image based on theimage data acquired by the image interface section 343 and an imagebased on the image data stored in the storage section 32 with the twoimages switched from one to the other. In this aspect, the firstprojection section may be the projection section 35 and the thirdprojection section may be the projection section 36, or vice versa.

A projection image projected by the projector 11 or 13 can thus beprojected by any of the remaining projectors out of the projectors 11,13, and 15. Further, the projectors 11 and 13 can each project theprojection image described above in a different direction. Projectionimages projected in a plurality of directions can therefore be switchedfrom one to another with high flexibility, whereby the convenienceprovided by the projection system 1 can be further improved.

In the projection system 1, in a case where the third projection sectiondisplays the image based on the image data stored in the first storagesection, the orientation of the image can be changed.

In the first aspect, when the projector 11 causes the projection section26 to display the image based on the image data stored in the storagesection 22 (projection image data 224, for example), the orientation ofthe image can be changed.

In the second aspect, when the projector 13 causes the projectionsection 36 to display the image based on the image data stored in thestorage section 32 (projection image data 324, for example), theorientation of the image can be changed.

The projectors 11 and 13 can therefore each project a projection imagein an orientation that allows a person who views the image to readilyvisually recognize the image.

In the projection system 1, the second projector includes a fourthprojection section that projects an image in a direction different froma direction in which the second projection section projects an image,and the second projector can cause the fourth projection section toproject an image based on the image data acquired by the secondacquisition section and an image based on the image data stored in thesecond storage section with the two images switched from one to theother.

In the first aspect, the projector 13 includes the projection section36, which projects an image in a direction different from the directionin which the projection section 35 projects an image. The projector 13can cause the projection section 36 to project an image based on theimage data acquired by the image interface section 343 and an imagebased on the image data stored in the storage section 32 (projectionimage data 324, for example) with the two images switched from one tothe other.

In the second aspect, the projector 11 includes the projection section26, which projects an image in a direction different from the directionin which the projection section 25 projects an image. The projector 11can cause the projection section 26 to project an image based on theimage data acquired by the image interface section 243 and an imagebased on the image data stored in the storage section 22 (projectionimage data 224, for example) with the two images switched from one tothe other.

A projection image projected by the projector 11 or 13 can thus beprojected by any of the remaining projectors out of the projectors 11,13, and 15. Further, the projectors 11 and 13 can each project theprojection image in a different direction. Projection images projectedin a plurality of directions can therefore be switched from one toanother with high flexibility, whereby the convenience provided by theprojection system 1 can be further improved.

In the projection system 1, in a case where the fourth projectionsection projects the image based on the image data stored in the secondstorage section, the orientation of the image can be changed.

In the first aspect, when the projector 13 causes the projection section35 to display the image based on the image data stored in the storagesection 32 (projection image data 324, for example), the orientation ofthe image can be changed.

In the second aspect, when the projector 11 causes the projectionsection 25 to display the image based on the image data stored in thestorage section 22 (projection image data 224, for example), theorientation of the image can be changed.

The projectors 11 and 13 can therefore each project a projection imagein an orientation that allows a person who views the image to readilyvisually recognize the image.

The embodiment described above is merely an example of a specific aspectto which the invention is applied and is not intended to restrict theinvention, and the invention can be applied in the form of differentaspects. For example, the pointing elements 201 and 203 used by the userin the projection system 1 are each not limited to a pen-shaped pointingelement, and the user's hand or finger, a laser pointer, a pointing rod,or any other object may be used, with the shape and size thereof notlimited to a specific shape or size.

In the embodiment described above, the position detecting sections 27and 37 image projection surfaces to identify the positions of thepointing elements 201 and 203, but not necessarily in the invention. Forexample, the imaging section 273 or 373 is not necessarily provided inthe main body of the projector 11 or 13. The imaging sections 273 and373 may be provided as portions separate from the main bodies of theprojectors 11 and 13. The imaging sections 273 and 373 may performimaging in the direction toward the side of the flat surfaces PL1 andPL2, which are projection surfaces, or in the direction toward the frontthereof. Further, the projector 11 may detect an operation position onthe basis of image data captured by a plurality of imaging sections 273.The same holds true for the projector 13.

The function that allows the position detecting section 27 of theprojector 11 to detect operation of the pointing element 201 and/or thefunction that allows the position detecting section 37 of the projector13 to detect operation of the pointing element 203 may be achieved asthe function of another apparatus independent of the projectors 11 and13.

At least part of the functional blocks shown in the block diagrams maybe achieved by hardware or may be achieved by cooperation of hardwareand software, and the configurations in which the independent hardwareresources are arranged as shown in the diagrams are not necessarilyemployed.

Further, the program executed by each of the control sections may bestored in the storage section or another storage device (not shown).Further, the control section may acquire the program stored in anexternal device and execute the program.

The invention may be configured in an aspect of a program executed by acomputer to achieve the method for controlling the projectors 11, 13,and 15 described above, a recording medium on which the programs is sorecorded as to be readable by a computer, or a transmission medium thattransmits the program. The recording medium described above can be amagnetic or an optical recording medium or a semiconductor memorydevice. Specific example of the recording medium may include a flexibledisk, an HDD (hard disk drive), a CD-ROM (compact disk read onlymemory), a DVD (digital versatile disk), a Blu-ray (registeredtrademark) disc, a magneto-optical disk, a flash memory, and a portablerecording medium, such as a card-shaped recording medium, or an immobilerecording medium. The recording medium described above may instead be aRAM (random access memory), a ROM (read only memory), or an HDD or anyother nonvolatile storage device that are internal storage devicesprovided in each apparatus provided in the projection system 1 or in anexternal apparatus connected to the apparatus.

In addition, the specific detailed configuration of each of otherportions of the apparatus that form the projection system 1 can also bearbitrarily changed to the extent that the change does not depart fromthe substance of the invention.

What is claimed is:
 1. A projection system comprising: a first projectorthat projects an image based on image data in a first projectiondirection; a second projector that projects an image based on image datain a second projection direction; and a storage section that stores theimage data representing the image projected by the first projector,wherein the image projected by the second projector is allowed to beswitched to the image based on the image data stored in the storagesection.
 2. The projection system according to claim 1 further includesan acceptance section that accepts an instruction input, wherein theimage projected by the second projector is switched to the image basedon the image data stored in the storage section in accordance with theinstruction input accepted by the acceptance section.
 3. A projectionsystem comprising: a first projector including a first acquisitionsection that acquires image data, a first projection section thatprojects an image based on the image data acquired by the firstacquisition section, a first storage section that stores the image datarepresenting the image projected by the first projection section, and afirst communication section that transmits the image data stored in thefirst storage section to the second projector; and a second projectorincluding a second acquisition section that acquires image data, asecond projection section that projects an image based on the image dataacquired by the second acquisition section, a second communicationsection that receives the image data from the first projector, and asecond storage section that stores the image data received by the secondcommunication section, wherein the second projector can perform anaction in which the second projection section projects the image basedon the image data acquired by the second acquisition section and anaction in which the second projection section projects the image basedon the image data stored in the second storage section with the twoactions switched from one to the other.
 4. The projection systemaccording to claim 3, wherein the first projector includes a switchingcontrol section that produces control data that instructs the secondprojector to perform image switching and causes the first communicationsection to transmit the control data to the second projector, and thesecond projector, upon reception of the control data via the secondcommunication section, switches the action in which the secondprojection section projects the image based on the image data acquiredby the second acquiring section to the action in which the secondprojection section projects the image based on the image data stored inthe second storage section and vice versa.
 5. The projection systemaccording to claim 4, wherein the first projector projects an image foroperation based on data representing the image for operation, andincludes an acceptance section that accepts operation performed on theimage for operation projected by the first projection section, and theswitching control section produces the control data based on theoperation accepted by the acceptance section and causes the firstcommunication section to transmit the control data to the secondprojector.
 6. The projection system according to claim 3, wherein thefirst projector includes a position detecting section that detects aposition input, and an image producing section that produces an imagebased on a position detected by the position detecting section, thefirst projection section projects an image based on combined image dataformed of image data representing the image produced by the imageproducing section combined with the image data acquired by the firstacquisition section, the first storage section stores the combined imagedata, and the first communication section transmits the combined imagedata stored in the storage section to the second projector.
 7. Theprojection system according to claim 3, wherein the first projectorincludes a third projection section that projects an image in adirection different from a direction in which the first projectionsection projects an image, and the first projector can cause the thirdprojection section to project an image based on the image data acquiredby the first acquisition section and an image based on the image datastored in the first storage section with the two images switched fromone to the other.
 8. The projection system according to claim 7, whereinin a case where the third projection section projects the image based onthe image data stored in the first storage section, the orientation ofthe image can be changed.
 9. The projection system according to claim 3,wherein the second projector includes a fourth projection section thatprojects an image in a direction different from a direction in which thesecond projection section projects an image, and the second projectorcan cause the fourth projection section to project an image based on theimage data acquired by the second acquisition section and an image basedon the image data stored in the second storage section with the twoimages switched from one to the other.
 10. The projector according toclaim 9, wherein in a case where the fourth projection section projectsthe image based on the image data stored in the second storage section,the orientation of the image can be changed.
 11. A method forcontrolling a projection system including a first projector thatprojects an image based on image data in a first projection directionand a second projector that projects an image based on image data in asecond projection direction, the method comprising storing the imagedata representing the image projected by the first projector andswitching the image projected by the second projector to the image basedon the stored image data.
 12. A method for controlling a projectionsystem including a first projector that projects an image based on imagedata in a first projection direction and a second projector thatprojects an image based on image data in a second projection direction,wherein the first projector causes a first acquisition section toacquire image data, projects an image based on the image data acquiredby the first acquisition section, stores the image data on the projectedimage, and transmits the stored image data to the second projector, andthe second projector causes a second acquisition section to acquireimage data, projects an image based on the image data acquired by thesecond acquisition section, and receives the image data from the firstprojector, stores the received image data, and performs an action ofprojecting the image based on the image data acquired by the secondacquisition section and an action of projecting the image based on thestored image data with the two actions switched from one to the other.